web3.js - Ethereum JavaScript API¶

web3.js is a collection of libraries which allow you to interact with a local or remote ethereum node, using a HTTP or IPC connection.

The following documentation will guide you through installing and running web3.js, as well as providing a API reference documentation with examples.

Contents:

Keyword Index, Search Page

Getting Started¶

The web3.js library is a collection of modules which contain specific functionality for the ethereum ecosystem.

The web3-eth is for the ethereum blockchain and smart contracts
The web3-shh is for the whisper protocol to communicate p2p and broadcast
The web3-bzz is for the swarm protocol, the decentralized file storage
The web3-utils contains useful helper functions for Dapp developers.

Adding web3.js¶

First you need to get web3.js into your project. This can be done using the following methods:

npm: npm install web3
meteor: meteor add ethereum:web3
pure js: link the dist/web3.min.js

After that you need to create a web3 instance and set a provider. Ethereum supported Browsers like Mist or MetaMask will have a ethereumProvider or web3.currentProvider available. For web3.js, check Web3.givenProvider. If this property is null you should connect to a remote/local node.

// in node.js use: var Web3 = require('web3');

var web3 = new Web3(Web3.givenProvider || "ws://localhost:8545");

That’s it! now you can use the web3 object.

Callbacks Promises Events¶

To help web3 integrate into all kind of projects with different standards we provide multiple ways to act on asynchronous functions.

Most web3.js objects allow a callback as the last parameter, as well as returning promises to chain functions.

Ethereum as a blockchain has different levels of finality and therefore needs to return multiple “stages” of an action. To cope with requirement we return a “promiEvent” for functions like web3.eth.sendTransaction or contract methods. This “promiEvent” is a promise combined with an event emitter to allow acting on different stages of action on the blockchain, like a transaction.

PromiEvents work like a normal promises with added on, once and off functions. This way developers can watch for additional events like on “receipt” or “transactionHash”.

web3.eth.sendTransaction({from: '0x123...', data: '0x432...'})
.once('transactionHash', function(hash){ ... })
.once('receipt', function(receipt){ ... })
.on('confirmation', function(confNumber, receipt){ ... })
.on('error', function(error){ ... })
.then(function(receipt){
    // will be fired once the receipt is mined
});

Glossary¶

json interface¶

The json interface is a json object describing the Application Binary Interface (ABI) for an Ethereum smart contract.

Using this json interface web3.js is able to create JavaScript object representing the smart contract and its methods and events using the web3.eth.Contract object.

Specification¶

Functions:

type: "function", "constructor" (can be omitted, defaulting to "function"; "fallback" also possible but not relevant in web3.js);
name: the name of the function (only present for function types);
constant: true if function is specified to not modify the blockchain state;
payable: true if function accepts ether, defaults to false;
stateMutability: a string with one of the following values: pure (specified to not read blockchain state), view (same as constant above), nonpayable and payable (same as payable above);
inputs: an array of objects, each of which contains:
- name: the name of the parameter;
- type: the canonical type of the parameter.
outputs: an array of objects same as inputs, can be omitted if no outputs exist.

Events:

type: always "event"
name: the name of the event;
inputs: an array of objects, each of which contains:
- name: the name of the parameter;
- type: the canonical type of the parameter.
- indexed: true if the field is part of the log’s topics, false if it one of the log’s data segment.
anonymous: true if the event was declared as anonymous.

Example¶

contract Test {
    uint a;
    address d = 0x12345678901234567890123456789012;

    function Test(uint testInt)  { a = testInt;}

    event Event(uint indexed b, bytes32 c);

    event Event2(uint indexed b, bytes32 c);

    function foo(uint b, bytes32 c) returns(address) {
        Event(b, c);
        return d;
    }
}

// would result in the JSON:
[{
    "type":"constructor",
    "payable":false,
    "stateMutability":"nonpayable"
    "inputs":[{"name":"testInt","type":"uint256"}],
  },{
    "type":"function",
    "name":"foo",
    "constant":false,
    "payable":false,
    "stateMutability":"nonpayable",
    "inputs":[{"name":"b","type":"uint256"}, {"name":"c","type":"bytes32"}],
    "outputs":[{"name":"","type":"address"}]
  },{
    "type":"event",
    "name":"Event",
    "inputs":[{"indexed":true,"name":"b","type":"uint256"}, {"indexed":false,"name":"c","type":"bytes32"}],
    "anonymous":false
  },{
    "type":"event",
    "name":"Event2",
    "inputs":[{"indexed":true,"name":"b","type":"uint256"},{"indexed":false,"name":"c","type":"bytes32"}],
    "anonymous":false
}]

Web3¶

This is the main (or ‘umbrella’) class of the web3.js library.

var Web3 = require('web3');

> Web3.utils
> Web3.version
> Web3.givenProvider
> Web3.providers
> Web3.modules

Web3.modules¶

Web3.modules

Will return an object with the classes of all major sub modules, to be able to instantiate them manually.

Returns¶

Object: A list of module constructors:

Eth - Constructor: The Eth module for interacting with the Ethereum network see web3.eth for more.
Net - Constructor: The Net module for interacting with network properties see web3.eth.net for more.
Personal - Constructor: The Personal module for interacting with the Ethereum accounts see web3.eth.personal for more.
Shh - Constructor: The Shh module for interacting with the whisper protocol see web3.shh for more.
Bzz - Constructor: The Bzz module for interacting with the swarm network see web3.bzz for more.

Example¶

Web3.modules
> {
    Eth: Eth(provider),
    Net: Net(provider),
    Personal: Personal(provider),
    Shh: Shh(provider),
    Bzz: Bzz(provider),
}

Web3 Instance¶

The Web3 class is an umbrella package to house all Ethereum related modules.

var Web3 = require('web3');

// "Web3.providers.givenProvider" will be set if in an Ethereum supported browser.
var web3 = new Web3(Web3.givenProvider || 'ws://some.local-or-remote.node:8546');

> web3.eth
> web3.shh
> web3.bzz
> web3.utils
> web3.version

version¶

Static accessible property of the Web3 class and property of the instance as well.

Web3.version
web3.version

Contains the current package version of the web3.js library.

Returns¶

String: The current version.

Example¶

web3.version;
> "1.2.3"

utils¶

Static accessible property of the Web3 class and property of the instance as well.

Web3.utils
web3.utils

Utility functions are also exposes on the Web3 class object directly.

See web3.utils for more.

setProvider¶

web3.setProvider(myProvider)
web3.eth.setProvider(myProvider)
web3.shh.setProvider(myProvider)
web3.bzz.setProvider(myProvider)
...

Will change the provider for its module.

Note

When called on the umbrella package web3 it will also set the provider for all sub modules web3.eth, web3.shh, etc EXCEPT web3.bzz which needs a separate provider at all times.

Parameters¶

Object - myProvider: a valid provider.

Returns¶

Boolean

Example¶

var Web3 = require('web3');
var web3 = new Web3('http://localhost:8545');
// or
var web3 = new Web3(new Web3.providers.HttpProvider('http://localhost:8545'));

// change provider
web3.setProvider('ws://localhost:8546');
// or
web3.setProvider(new Web3.providers.WebsocketProvider('ws://localhost:8546'));

// Using the IPC provider in node.js
var net = require('net');
var web3 = new Web3('/Users/myuser/Library/Ethereum/geth.ipc', net); // mac os path
// or
var web3 = new Web3(new Web3.providers.IpcProvider('/Users/myuser/Library/Ethereum/geth.ipc', net)); // mac os path
// on windows the path is: "\\\\.\\pipe\\geth.ipc"
// on linux the path is: "/users/myuser/.ethereum/geth.ipc"

providers¶

web3.providers
web3.eth.providers
web3.shh.providers
web3.bzz.providers
...

Contains the current available providers.

Value¶

Object with the following providers:

Object - HttpProvider: The HTTP provider is deprecated, as it won’t work for subscriptions.

Object - WebsocketProvider: The Websocket provider is the standard for usage in legacy browsers.

Object - IpcProvider: The IPC provider is used node.js dapps when running a local node. Gives the most secure connection.

Example¶

var Web3 = require('web3');
// use the given Provider, e.g in Mist, or instantiate a new websocket provider
var web3 = new Web3(Web3.givenProvider || 'ws://remotenode.com:8546');
// or
var web3 = new Web3(Web3.givenProvider || new Web3.providers.WebsocketProvider('ws://remotenode.com:8546'));

// Using the IPC provider in node.js
var net = require('net');

var web3 = new Web3('/Users/myuser/Library/Ethereum/geth.ipc', net); // mac os path
// or
var web3 = new Web3(new Web3.providers.IpcProvider('/Users/myuser/Library/Ethereum/geth.ipc', net)); // mac os path
// on windows the path is: "\\\\.\\pipe\\geth.ipc"
// on linux the path is: "/users/myuser/.ethereum/geth.ipc"

givenProvider¶

web3.givenProvider
web3.eth.givenProvider
web3.shh.givenProvider
web3.bzz.givenProvider
...

When using web3.js in an Ethereum compatible browser, it will set with the current native provider by that browser. Will return the given provider by the (browser) environment, otherwise null.

Returns¶

Object: The given provider set or null;

Example¶

currentProvider¶

web3.currentProvider
web3.eth.currentProvider
web3.shh.currentProvider
web3.bzz.currentProvider
...

Will return the current provider, otherwise null.

Returns¶

Object: The current provider set or null;

Example¶

BatchRequest¶

new web3.BatchRequest()
new web3.eth.BatchRequest()
new web3.shh.BatchRequest()
new web3.bzz.BatchRequest()

Class to create and execute batch requests.

Parameters¶

none

Returns¶

Object: With the following methods:

add(request): To add a request object to the batch call.

execute(): Will execute the batch request.

Example¶

var contract = new web3.eth.Contract(abi, address);

var batch = new web3.BatchRequest();
batch.add(web3.eth.getBalance.request('0x0000000000000000000000000000000000000000', 'latest', callback));
batch.add(contract.methods.balance(address).call.request({from: '0x0000000000000000000000000000000000000000'}, callback2));
batch.execute();

extend¶

web3.extend(methods)
web3.eth.extend(methods)
web3.shh.extend(methods)
web3.bzz.extend(methods)
...

Allows extending the web3 modules.

Note

You also have *.extend.formatters as additional formatter functions to be used for in and output formatting. Please see the source file for function details.

Parameters¶

methods - Object: Extension object with array of methods description objects as follows:
- property - String: (optional) The name of the property to add to the module. If no property is set it will be added to the module directly.
- methods - Array: The array of method descriptions:
  
  name - String: Name of the method to add.
  
  call - String: The RPC method name.
  
  params - Number: (optional) The number of parameters for that function. Default 0.
  
  inputFormatter - Array: (optional) Array of inputformatter functions. Each array item responds to a function parameter, so if you want some parameters not to be formatted, add a null instead.
  
  outputFormatter - ``Function: (optional) Can be used to format the output of the method.

Returns¶

Object: The extended module.

Example¶

web3.extend({
    property: 'myModule',
    methods: [{
        name: 'getBalance',
        call: 'eth_getBalance',
        params: 2,
        inputFormatter: [web3.extend.formatters.inputAddressFormatter, web3.extend.formatters.inputDefaultBlockNumberFormatter],
        outputFormatter: web3.utils.hexToNumberString
    },{
        name: 'getGasPriceSuperFunction',
        call: 'eth_gasPriceSuper',
        params: 2,
        inputFormatter: [null, web3.utils.numberToHex]
    }]
});

web3.extend({
    methods: [{
        name: 'directCall',
        call: 'eth_callForFun',
    }]
});

console.log(web3);
> Web3 {
    myModule: {
        getBalance: function(){},
        getGasPriceSuperFunction: function(){}
    },
    directCall: function(){},
    eth: Eth {...},
    bzz: Bzz {...},
    ...
}

web3.eth¶

The web3-eth package allows you to interact with an Ethereum blockchain and Ethereum smart contracts.

var Eth = require('web3-eth');

// "Eth.providers.givenProvider" will be set if in an Ethereum supported browser.
var eth = new Eth(Eth.givenProvider || 'ws://some.local-or-remote.node:8546');

// or using the web3 umbrella package

var Web3 = require('web3');
var web3 = new Web3(Web3.givenProvider || 'ws://some.local-or-remote.node:8546');

// -> web3.eth

Note on checksum addresses¶

All Ethereum addresses returned by functions of this package are returned as checksum addresses. This means some letters are uppercase and some are lowercase. Based on that it will calculate a checksum for the address and prove its correctness. Incorrect checksum addresses will throw an error when passed into functions. If you want to circumvent the checksum check you can make an address all lower- or uppercase.

Example¶

web3.eth.getAccounts(console.log);
> ["0x11f4d0A3c12e86B4b5F39B213F7E19D048276DAe" ,"0x85F43D8a49eeB85d32Cf465507DD71d507100C1d"]

setProvider¶

web3.setProvider(myProvider)
web3.eth.setProvider(myProvider)
web3.shh.setProvider(myProvider)
web3.bzz.setProvider(myProvider)
...

Will change the provider for its module.

Note

When called on the umbrella package web3 it will also set the provider for all sub modules web3.eth, web3.shh, etc EXCEPT web3.bzz which needs a separate provider at all times.

Parameters¶

Object - myProvider: a valid provider.

Returns¶

Boolean

Example¶

var Web3 = require('web3');
var web3 = new Web3('http://localhost:8545');
// or
var web3 = new Web3(new Web3.providers.HttpProvider('http://localhost:8545'));

// change provider
web3.setProvider('ws://localhost:8546');
// or
web3.setProvider(new Web3.providers.WebsocketProvider('ws://localhost:8546'));

// Using the IPC provider in node.js
var net = require('net');
var web3 = new Web3('/Users/myuser/Library/Ethereum/geth.ipc', net); // mac os path
// or
var web3 = new Web3(new Web3.providers.IpcProvider('/Users/myuser/Library/Ethereum/geth.ipc', net)); // mac os path
// on windows the path is: "\\\\.\\pipe\\geth.ipc"
// on linux the path is: "/users/myuser/.ethereum/geth.ipc"

providers¶

web3.providers
web3.eth.providers
web3.shh.providers
web3.bzz.providers
...

Contains the current available providers.

Value¶

Object with the following providers:

Object - HttpProvider: The HTTP provider is deprecated, as it won’t work for subscriptions.

Object - WebsocketProvider: The Websocket provider is the standard for usage in legacy browsers.

Object - IpcProvider: The IPC provider is used node.js dapps when running a local node. Gives the most secure connection.

Example¶

var Web3 = require('web3');
// use the given Provider, e.g in Mist, or instantiate a new websocket provider
var web3 = new Web3(Web3.givenProvider || 'ws://remotenode.com:8546');
// or
var web3 = new Web3(Web3.givenProvider || new Web3.providers.WebsocketProvider('ws://remotenode.com:8546'));

// Using the IPC provider in node.js
var net = require('net');

var web3 = new Web3('/Users/myuser/Library/Ethereum/geth.ipc', net); // mac os path
// or
var web3 = new Web3(new Web3.providers.IpcProvider('/Users/myuser/Library/Ethereum/geth.ipc', net)); // mac os path
// on windows the path is: "\\\\.\\pipe\\geth.ipc"
// on linux the path is: "/users/myuser/.ethereum/geth.ipc"

givenProvider¶

web3.givenProvider
web3.eth.givenProvider
web3.shh.givenProvider
web3.bzz.givenProvider
...

When using web3.js in an Ethereum compatible browser, it will set with the current native provider by that browser. Will return the given provider by the (browser) environment, otherwise null.

Returns¶

Object: The given provider set or null;

Example¶

currentProvider¶

web3.currentProvider
web3.eth.currentProvider
web3.shh.currentProvider
web3.bzz.currentProvider
...

Will return the current provider, otherwise null.

Returns¶

Object: The current provider set or null;

Example¶

BatchRequest¶

new web3.BatchRequest()
new web3.eth.BatchRequest()
new web3.shh.BatchRequest()
new web3.bzz.BatchRequest()

Class to create and execute batch requests.

Parameters¶

none

Returns¶

Object: With the following methods:

add(request): To add a request object to the batch call.

execute(): Will execute the batch request.

Example¶

var contract = new web3.eth.Contract(abi, address);

var batch = new web3.BatchRequest();
batch.add(web3.eth.getBalance.request('0x0000000000000000000000000000000000000000', 'latest', callback));
batch.add(contract.methods.balance(address).call.request({from: '0x0000000000000000000000000000000000000000'}, callback2));
batch.execute();

extend¶

web3.extend(methods)
web3.eth.extend(methods)
web3.shh.extend(methods)
web3.bzz.extend(methods)
...

Allows extending the web3 modules.

Note

You also have *.extend.formatters as additional formatter functions to be used for in and output formatting. Please see the source file for function details.

Parameters¶

methods - Object: Extension object with array of methods description objects as follows:
- property - String: (optional) The name of the property to add to the module. If no property is set it will be added to the module directly.
- methods - Array: The array of method descriptions:
  
  name - String: Name of the method to add.
  
  call - String: The RPC method name.
  
  params - Number: (optional) The number of parameters for that function. Default 0.
  
  inputFormatter - Array: (optional) Array of inputformatter functions. Each array item responds to a function parameter, so if you want some parameters not to be formatted, add a null instead.
  
  outputFormatter - ``Function: (optional) Can be used to format the output of the method.

Returns¶

Object: The extended module.

Example¶

web3.extend({
    property: 'myModule',
    methods: [{
        name: 'getBalance',
        call: 'eth_getBalance',
        params: 2,
        inputFormatter: [web3.extend.formatters.inputAddressFormatter, web3.extend.formatters.inputDefaultBlockNumberFormatter],
        outputFormatter: web3.utils.hexToNumberString
    },{
        name: 'getGasPriceSuperFunction',
        call: 'eth_gasPriceSuper',
        params: 2,
        inputFormatter: [null, web3.utils.numberToHex]
    }]
});

web3.extend({
    methods: [{
        name: 'directCall',
        call: 'eth_callForFun',
    }]
});

console.log(web3);
> Web3 {
    myModule: {
        getBalance: function(){},
        getGasPriceSuperFunction: function(){}
    },
    directCall: function(){},
    eth: Eth {...},
    bzz: Bzz {...},
    ...
}

defaultAccount¶

web3.eth.defaultAccount

This default address is used as the default "from" property, if no "from" property is specified in for the following methods:

web3.eth.sendTransaction()
web3.eth.call()
new web3.eth.Contract() -> myContract.methods.myMethod().call()
new web3.eth.Contract() -> myContract.methods.myMethod().send()

Property¶

String - 20 Bytes: Any ethereum address. You should have the private key for that address in your node or keystore. (Default is undefined)

Example¶

web3.eth.defaultAccount;
> undefined

// set the default account
web3.eth.defaultAccount = '0x11f4d0A3c12e86B4b5F39B213F7E19D048276DAe';

defaultBlock¶

web3.eth.defaultBlock

The default block is used for certain methods. You can override it by passing in the defaultBlock as last parameter. The default value is “latest”.

web3.eth.getBalance()
web3.eth.getCode()
web3.eth.getTransactionCount()
web3.eth.getStorageAt()
web3.eth.call()
new web3.eth.Contract() -> myContract.methods.myMethod().call()

Property¶

Default block parameters can be one of the following:

Number: A block number
"genesis" - String: The genesis block
"latest" - String: The latest block (current head of the blockchain)
"pending" - String: The currently mined block (including pending transactions)

Default is "latest"

Example¶

web3.eth.defaultBlock;
> "latest"

// set the default block
web3.eth.defaultBlock = 231;

defaultHardfork¶

web3.eth.defaultHardfork

The default hardfork property is used for signing transactions locally.

Property¶

The default hardfork property can be one of the following:

"chainstart" - String
"homestead" - String
"dao" - String
"tangerineWhistle" - String
"spuriousDragon" - String
"byzantium" - String
"constantinople" - String
"petersburg" - String
"istanbul" - String

Default is "petersburg"

Example¶

web3.eth.defaultHardfork;
> "petersburg"

// set the default block
web3.eth.defaultHardfork = 'istanbul';

defaultChain¶

web3.eth.defaultChain

The default chain property is used for signing transactions locally.

Property¶

The default chain property can be one of the following:

"mainnet" - String
"goerli" - String
"kovan" - String
"rinkeby" - String
"ropsten" - String

Default is "mainnet"

Example¶

web3.eth.defaultChain;
> "mainnet"

// set the default chain
web3.eth.defaultChain = 'goerli';

defaultCommon¶

web3.eth.defaultCommon

The default common property is used for signing transactions locally.

Property¶

The default common property does contain the following Common object:

customChain - Object: The custom chain properties
- name - string: (optional) The name of the chain
- networkId - number: Network ID of the custom chain
- chainId - number: Chain ID of the custom chain
baseChain - string: (optional) mainnet, goerli, kovan, rinkeby, or ropsten
hardfork - string: (optional) chainstart, homestead, dao, tangerineWhistle, spuriousDragon, byzantium, constantinople, petersburg, or istanbul

Default is undefined.

Example¶

web3.eth.defaultCommon;
> {customChain: {name: 'custom-network', chainId: 1, networkId: 1}, baseChain: 'mainnet', hardfork: 'petersburg'}

// set the default common
web3.eth.defaultCommon = {customChain: {name: 'custom-network', chainId: 1, networkId: 1}, baseChain: 'mainnet', hardfork: 'petersburg'};

transactionBlockTimeout¶

web3.eth.transactionBlockTimeout

The transactionBlockTimeout will be used over a socket based connection. This option does define the amount of new blocks it should wait until the first confirmation happens. This means the PromiEvent rejects with a timeout error when the timeout got exceeded.

Returns¶

number: The current value of transactionBlockTimeout (default: 50)

transactionConfirmationBlocks¶

web3.eth.transactionConfirmationBlocks

This defines the number of blocks it requires until a transaction will be handled as confirmed.

Returns¶

number: The current value of transactionConfirmationBlocks (default: 24)

transactionPollingTimeout¶

web3.eth.transactionPollingTimeout

The transactionPollingTimeout will be used over a HTTP connection. This option defines the number of seconds Web3 will wait for a receipt which confirms that a transaction was mined by the network. NB: If this method times out, the transaction may still be pending.

Returns¶

number: The current value of transactionPollingTimeout (default: 750)

getProtocolVersion¶

web3.eth.getProtocolVersion([callback])

Returns the ethereum protocol version of the node.

Returns¶

Promise returns String: the protocol version.

Example¶

web3.eth.getProtocolVersion()
.then(console.log);
> "63"

isSyncing¶

web3.eth.isSyncing([callback])

Checks if the node is currently syncing and returns either a syncing object, or false.

Returns¶

Promise returns Object|Boolean - A sync object when the node is currently syncing or false:

startingBlock - Number: The block number where the sync started.

currentBlock - Number: The block number where at which block the node currently synced to already.

highestBlock - Number: The estimated block number to sync to.

knownStates - Number: The estimated states to download

pulledStates - Number: The already downloaded states

Example¶

web3.eth.isSyncing()
.then(console.log);

> {
    startingBlock: 100,
    currentBlock: 312,
    highestBlock: 512,
    knownStates: 234566,
    pulledStates: 123455
}

getCoinbase¶

getCoinbase([callback])

Returns the coinbase address to which mining rewards will go.

Returns¶

Promise returns String - bytes 20: The coinbase address set in the node for mining rewards.

Example¶

web3.eth.getCoinbase()
.then(console.log);
> "0x11f4d0A3c12e86B4b5F39B213F7E19D048276DAe"

isMining¶

web3.eth.isMining([callback])

Checks whether the node is mining or not.

Returns¶

Promise returns Boolean: true if the node is mining, otherwise false.

Example¶

web3.eth.isMining()
.then(console.log);
> true

getHashrate¶

web3.eth.getHashrate([callback])

Returns the number of hashes per second that the node is mining with.

Returns¶

Promise returns Number: Number of hashes per second.

Example¶

web3.eth.getHashrate()
.then(console.log);
> 493736

getGasPrice¶

web3.eth.getGasPrice([callback])

Returns the current gas price oracle. The gas price is determined by the last few blocks median gas price.

Returns¶

Promise returns String - Number string of the current gas price in wei.

See the A note on dealing with big numbers in JavaScript.

Example¶

web3.eth.getGasPrice()
.then(console.log);
> "20000000000"

getAccounts¶

web3.eth.getAccounts([callback])

Returns a list of accounts the node controls.

Returns¶

Promise returns Array - An array of addresses controlled by node.

Example¶

web3.eth.getAccounts()
.then(console.log);
> ["0x11f4d0A3c12e86B4b5F39B213F7E19D048276DAe", "0xDCc6960376d6C6dEa93647383FfB245CfCed97Cf"]

getBlockNumber¶

web3.eth.getBlockNumber([callback])

Returns the current block number.

Returns¶

Promise returns Number - The number of the most recent block.

Example¶

web3.eth.getBlockNumber()
.then(console.log);
> 2744

getBalance¶

web3.eth.getBalance(address [, defaultBlock] [, callback])

Get the balance of an address at a given block.

Parameters¶

String - The address to get the balance of.
Number|String|BN|BigNumber - (optional) If you pass this parameter it will not use the default block set with web3.eth.defaultBlock. Pre-defined block numbers as "latest", "earlist", "pending", and "genesis" can also be used.
Function - (optional) Optional callback, returns an error object as first parameter and the result as second.

Returns¶

Promise returns String - The current balance for the given address in wei.

See the A note on dealing with big numbers in JavaScript.

Example¶

web3.eth.getBalance("0x407d73d8a49eeb85d32cf465507dd71d507100c1")
.then(console.log);
> "1000000000000"

getStorageAt¶

web3.eth.getStorageAt(address, position [, defaultBlock] [, callback])

Get the storage at a specific position of an address.

Parameters¶

String - The address to get the storage from.
Number|String|BN|BigNumber - The index position of the storage.
Number|String|BN|BigNumber - (optional) If you pass this parameter it will not use the default block set with web3.eth.defaultBlock. Pre-defined block numbers as "latest", "earlist", "pending", and "genesis" can also be used.
Function - (optional) Optional callback, returns an error object as first parameter and the result as second.

Returns¶

Promise returns String - The value in storage at the given position.

Example¶

web3.eth.getStorageAt("0x407d73d8a49eeb85d32cf465507dd71d507100c1", 0)
.then(console.log);
> "0x033456732123ffff2342342dd12342434324234234fd234fd23fd4f23d4234"

getCode¶

web3.eth.getCode(address [, defaultBlock] [, callback])

Get the code at a specific address.

Parameters¶

String - The address to get the code from.
Number|String|BN|BigNumber - (optional) If you pass this parameter it will not use the default block set with web3.eth.defaultBlock. Pre-defined block numbers as "latest", "earlist", "pending", and "genesis" can also be used.
Function - (optional) Optional callback, returns an error object as first parameter and the result as second.

Returns¶

Promise returns String - The data at given address address.

Example¶

web3.eth.getCode("0xd5677cf67b5aa051bb40496e68ad359eb97cfbf8")
.then(console.log);
> "0x600160008035811a818181146012578301005b601b6001356025565b8060005260206000f25b600060078202905091905056"

getBlock¶

web3.eth.getBlock(blockHashOrBlockNumber [, returnTransactionObjects] [, callback])

Returns a block matching the block number or block hash.

Parameters¶

String|Number|BN|BigNumber - The block number or block hash. Or the string "genesis", "latest", "earliest", or "pending" as in the default block parameter.
Boolean - (optional, default false) If specified true, the returned block will contain all transactions as objects. By default it is false so, there is no need to explictly specify false. And, if false it will only contains the transaction hashes.
Function - (optional) Optional callback, returns an error object as first parameter and the result as second.

Returns¶

Promise returns Object - The block object:

number - Number: The block number. null when its pending block.

hash 32 Bytes - String: Hash of the block. null when its pending block.

parentHash 32 Bytes - String: Hash of the parent block.

nonce 8 Bytes - String: Hash of the generated proof-of-work. null when its pending block.

sha3Uncles 32 Bytes - String: SHA3 of the uncles data in the block.

logsBloom 256 Bytes - String: The bloom filter for the logs of the block. null when its pending block.

transactionsRoot 32 Bytes - String: The root of the transaction trie of the block

stateRoot 32 Bytes - String: The root of the final state trie of the block.

miner - String: The address of the beneficiary to whom the mining rewards were given.

difficulty - String: Integer of the difficulty for this block.

totalDifficulty - String: Integer of the total difficulty of the chain until this block.

extraData - String: The “extra data” field of this block.

size - Number: Integer the size of this block in bytes.

gasLimit - Number: The maximum gas allowed in this block.

gasUsed - Number: The total used gas by all transactions in this block.

timestamp - Number: The unix timestamp for when the block was collated.

transactions - Array: Array of transaction objects, or 32 Bytes transaction hashes depending on the returnTransactionObjects parameter.

uncles - Array: Array of uncle hashes.

Example¶

web3.eth.getBlock(3150)
.then(console.log);

> {
    "number": 3,
    "hash": "0xef95f2f1ed3ca60b048b4bf67cde2195961e0bba6f70bcbea9a2c4e133e34b46",
    "parentHash": "0x2302e1c0b972d00932deb5dab9eb2982f570597d9d42504c05d9c2147eaf9c88",
    "nonce": "0xfb6e1a62d119228b",
    "sha3Uncles": "0x1dcc4de8dec75d7aab85b567b6ccd41ad312451b948a7413f0a142fd40d49347",
    "logsBloom": "0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
    "transactionsRoot": "0x3a1b03875115b79539e5bd33fb00d8f7b7cd61929d5a3c574f507b8acf415bee",
    "stateRoot": "0xf1133199d44695dfa8fd1bcfe424d82854b5cebef75bddd7e40ea94cda515bcb",
    "miner": "0x8888f1f195afa192cfee860698584c030f4c9db1",
    "difficulty": '21345678965432',
    "totalDifficulty": '324567845321',
    "size": 616,
    "extraData": "0x",
    "gasLimit": 3141592,
    "gasUsed": 21662,
    "timestamp": 1429287689,
    "transactions": [
        "0x9fc76417374aa880d4449a1f7f31ec597f00b1f6f3dd2d66f4c9c6c445836d8b"
    ],
    "uncles": []
}

getBlockTransactionCount¶

web3.eth.getBlockTransactionCount(blockHashOrBlockNumber [, callback])

Returns the number of transaction in a given block.

Parameters¶

String|Number|BN|BigNumber - The block number or hash. Or the string "genesis", "latest", "earliest", or "pending" as in the default block parameter.
Function - (optional) Optional callback, returns an error object as first parameter and the result as second.

Returns¶

Promise returns Number - The number of transactions in the given block.

Example¶

web3.eth.getBlockTransactionCount("0x407d73d8a49eeb85d32cf465507dd71d507100c1")
.then(console.log);
> 1

getBlockUncleCount¶

web3.eth.getBlockUncleCount(blockHashOrBlockNumber [, callback])

Returns the number of uncles in a block from a block matching the given block hash.

Parameters¶

String|Number|BN|BigNumber - The block number or hash. Or the string "genesis", "latest", "earliest", or "pending" as in the default block parameter.
Function - (optional) Optional callback, returns an error object as first parameter and the result as second.

Returns¶

Promise returns Number - The number of transactions in the given block.

Example¶

web3.eth.getBlockUncleCount("0x407d73d8a49eeb85d32cf465507dd71d507100c1")
.then(console.log);
> 1

getUncle¶

web3.eth.getUncle(blockHashOrBlockNumber, uncleIndex [, returnTransactionObjects] [, callback])

Returns a blocks uncle by a given uncle index position.

Parameters¶

String|Number|BN|BigNumber - The block number or hash. Or the string "genesis", "latest", "earliest", or "pending" as in the default block parameter.
Number - The index position of the uncle.
Boolean - (optional, default false) If specified true, the returned block will contain all transactions as objects. By default it is false so, there is no need to explictly specify false. And, if false it will only contains the transaction hashes.
Function - (optional) Optional callback, returns an error object as first parameter and the result as second.

Returns¶

Promise returns Object - the returned uncle. For a return value see web3.eth.getBlock().

Note

An uncle doesn’t contain individual transactions.

Example¶

web3.eth.getUncle(500, 0)
.then(console.log);
> // see web3.eth.getBlock

getTransaction¶

web3.eth.getTransaction(transactionHash [, callback])

Returns a transaction matching the given transaction hash.

Parameters¶

String - The transaction hash.
Function - (optional) Optional callback, returns an error object as first parameter and the result as second.

Returns¶

Promise returns Object - A transaction object its hash transactionHash:

hash 32 Bytes - String: Hash of the transaction.

nonce - Number: The number of transactions made by the sender prior to this one.

blockHash 32 Bytes - String: Hash of the block where this transaction was in. null when its pending.

blockNumber - Number: Block number where this transaction was in. null when its pending.

transactionIndex - Number: Integer of the transactions index position in the block. null when its pending.

from - String: Address of the sender.

to - String: Address of the receiver. null when its a contract creation transaction.

value - String: Value transferred in wei.

gasPrice - String: Gas price provided by the sender in wei.

gas - Number: Gas provided by the sender.

input - String: The data sent along with the transaction.

Example¶

web3.eth.getTransaction('0x9fc76417374aa880d4449a1f7f31ec597f00b1f6f3dd2d66f4c9c6c445836d8b§234')
.then(console.log);

> {
    "hash": "0x9fc76417374aa880d4449a1f7f31ec597f00b1f6f3dd2d66f4c9c6c445836d8b",
    "nonce": 2,
    "blockHash": "0xef95f2f1ed3ca60b048b4bf67cde2195961e0bba6f70bcbea9a2c4e133e34b46",
    "blockNumber": 3,
    "transactionIndex": 0,
    "from": "0xa94f5374fce5edbc8e2a8697c15331677e6ebf0b",
    "to": "0x6295ee1b4f6dd65047762f924ecd367c17eabf8f",
    "value": '123450000000000000',
    "gas": 314159,
    "gasPrice": '2000000000000',
    "input": "0x57cb2fc4"
}

getTransactionFromBlock¶

getTransactionFromBlock(hashStringOrNumber, indexNumber [, callback])

Returns a transaction based on a block hash or number and the transactions index position.

Parameters¶

String|Number|BN|BigNumber - A block number or hash. Or the string "genesis", "latest", "earliest", or "pending" as in the default block parameter.
Number - The transactions index position.
Function - (optional) Optional callback, returns an error object as first parameter and the result as second.

Returns¶

Promise returns Object - A transaction object, see web3.eth.getTransaction:

Example¶

var transaction = web3.eth.getTransactionFromBlock('0x4534534534', 2)
.then(console.log);
> // see web3.eth.getTransaction

getTransactionReceipt¶

web3.eth.getTransactionReceipt(hash [, callback])

Returns the receipt of a transaction by transaction hash.

Note

The receipt is not available for pending transactions and returns null.

Parameters¶

String - The transaction hash.
Function - (optional) Optional callback, returns an error object as first parameter and the result as second.

Returns¶

Promise returns Object - A transaction receipt object, or null when no receipt was found:

status - Boolean: TRUE if the transaction was successful, FALSE, if the EVM reverted the transaction.

blockHash 32 Bytes - String: Hash of the block where this transaction was in.

blockNumber - Number: Block number where this transaction was in.

transactionHash 32 Bytes - String: Hash of the transaction.

transactionIndex- Number: Integer of the transactions index position in the block.

from - String: Address of the sender.

to - String: Address of the receiver. null when its a contract creation transaction.

contractAddress - String: The contract address created, if the transaction was a contract creation, otherwise null.

cumulativeGasUsed - Number: The total amount of gas used when this transaction was executed in the block.

gasUsed- Number: The amount of gas used by this specific transaction alone.

logs - Array: Array of log objects, which this transaction generated.

Example¶

var receipt = web3.eth.getTransactionReceipt('0x9fc76417374aa880d4449a1f7f31ec597f00b1f6f3dd2d66f4c9c6c445836d8b')
.then(console.log);

> {
  "status": true,
  "transactionHash": "0x9fc76417374aa880d4449a1f7f31ec597f00b1f6f3dd2d66f4c9c6c445836d8b",
  "transactionIndex": 0,
  "blockHash": "0xef95f2f1ed3ca60b048b4bf67cde2195961e0bba6f70bcbea9a2c4e133e34b46",
  "blockNumber": 3,
  "contractAddress": "0x11f4d0A3c12e86B4b5F39B213F7E19D048276DAe",
  "cumulativeGasUsed": 314159,
  "gasUsed": 30234,
  "logs": [{
         // logs as returned by getPastLogs, etc.
     }, ...]
}

getTransactionCount¶

web3.eth.getTransactionCount(address [, defaultBlock] [, callback])

Get the numbers of transactions sent from this address.

Parameters¶

String - The address to get the numbers of transactions from.
Number|String|BN|BigNumber - (optional) If you pass this parameter it will not use the default block set with web3.eth.defaultBlock. Pre-defined block numbers as "latest", "earlist", "pending", and "genesis" can also be used.
Function - (optional) Optional callback, returns an error object as first parameter and the result as second.

Returns¶

Promise returns Number - The number of transactions sent from the given address.

Example¶

web3.eth.getTransactionCount("0x11f4d0A3c12e86B4b5F39B213F7E19D048276DAe")
.then(console.log);
> 1

sendTransaction¶

web3.eth.sendTransaction(transactionObject [, callback])

Sends a transaction to the network.

Parameters¶

Object - The transaction object to send:
- from - String|Number: The address for the sending account. Uses the web3.eth.defaultAccount property, if not specified. Or an address or index of a local wallet in web3.eth.accounts.wallet.
- to - String: (optional) The destination address of the message, left undefined for a contract-creation transaction.
- value - Number|String|BN|BigNumber: (optional) The value transferred for the transaction in wei, also the endowment if it’s a contract-creation transaction.
- gas - Number: (optional, default: To-Be-Determined) The amount of gas to use for the transaction (unused gas is refunded).
- gasPrice - Number|String|BN|BigNumber: (optional) The price of gas for this transaction in wei, defaults to web3.eth.gasPrice.
- data - String: (optional) Either a ABI byte string containing the data of the function call on a contract, or in the case of a contract-creation transaction the initialisation code.
- nonce - Number: (optional) Integer of a nonce. This allows to overwrite your own pending transactions that use the same nonce.
- chain - String: (optional) Defaults to mainnet.
- hardfork - String: (optional) Defaults to petersburg.
- common - Object: (optional) The common object
  
  customChain - Object: The custom chain properties
  
  name - string: (optional) The name of the chain
  
  networkId - number: Network ID of the custom chain
  
  chainId - number: Chain ID of the custom chain
  
  baseChain - string: (optional) mainnet, goerli, kovan, rinkeby, or ropsten
  
  hardfork - string: (optional) chainstart, homestead, dao, tangerineWhistle, spuriousDragon, byzantium, constantinople, petersburg, or istanbul
callback - Function: (optional) Optional callback, returns an error object as first parameter and the result as second.

Note

The from property can also be an address or index from the web3.eth.accounts.wallet. It will then sign locally using the private key of that account, and send the transaction via web3.eth.sendSignedTransaction(). If the properties chain and hardfork or common are not set, Web3 will try to set appropriate values by

querying the network for its chainId and networkId.

Returns¶

The callback will return the 32 bytes transaction hash.

PromiEvent: A promise combined event emitter. Will be resolved when the transaction receipt is available. Additionally the following events are available:

"transactionHash" returns String: Is fired right after the transaction is sent and a transaction hash is available.
"receipt" returns Object: Is fired when the transaction receipt is available.
"confirmation" returns Number, Object: Is fired for every confirmation up to the 12th confirmation. Receives the confirmation number as the first and the receipt as the second argument. Fired from confirmation 0 on, which is the block where its minded.

"error" returns Error and Object|undefined: Is fired if an error occurs during sending. If the transaction was rejected by the network with a receipt, the second parameter will be the receipt.

Example¶

// compiled solidity source code using https://remix.ethereum.org
var code = "603d80600c6000396000f3007c01000000000000000000000000000000000000000000000000000000006000350463c6888fa18114602d57005b6007600435028060005260206000f3";


// using the callback
web3.eth.sendTransaction({
    from: '0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe',
    data: code // deploying a contracrt
}, function(error, hash){
    ...
});

// using the promise
web3.eth.sendTransaction({
    from: '0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe',
    to: '0x11f4d0A3c12e86B4b5F39B213F7E19D048276DAe',
    value: '1000000000000000'
})
.then(function(receipt){
    ...
});


// using the event emitter
web3.eth.sendTransaction({
    from: '0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe',
    to: '0x11f4d0A3c12e86B4b5F39B213F7E19D048276DAe',
    value: '1000000000000000'
})
.on('transactionHash', function(hash){
    ...
})
.on('receipt', function(receipt){
    ...
})
.on('confirmation', function(confirmationNumber, receipt){ ... })
.on('error', console.error); // If a out of gas error, the second parameter is the receipt.

sendSignedTransaction¶

web3.eth.sendSignedTransaction(signedTransactionData [, callback])

Sends an already signed transaction, generated for example using web3.eth.accounts.signTransaction.

Parameters¶

String - Signed transaction data in HEX format
Function - (optional) Optional callback, returns an error object as first parameter and the result as second.

Returns¶

PromiEvent: A promise combined event emitter. Will be resolved when the transaction receipt is available.

Please see the return values for web3.eth.sendTransaction for details.

Example¶

var Tx = require('ethereumjs-tx').Transaction;
var privateKey = Buffer.from('e331b6d69882b4cb4ea581d88e0b604039a3de5967688d3dcffdd2270c0fd109', 'hex');

var rawTx = {
  nonce: '0x00',
  gasPrice: '0x09184e72a000',
  gasLimit: '0x2710',
  to: '0x0000000000000000000000000000000000000000',
  value: '0x00',
  data: '0x7f7465737432000000000000000000000000000000000000000000000000000000600057'
}

var tx = new Tx(rawTx, {'chain':'ropsten'});
tx.sign(privateKey);

var serializedTx = tx.serialize();

// console.log(serializedTx.toString('hex'));
// 0xf889808609184e72a00082271094000000000000000000000000000000000000000080a47f74657374320000000000000000000000000000000000000000000000000000006000571ca08a8bbf888cfa37bbf0bb965423625641fc956967b81d12e23709cead01446075a01ce999b56a8a88504be365442ea61239198e23d1fce7d00fcfc5cd3b44b7215f

web3.eth.sendSignedTransaction('0x' + serializedTx.toString('hex'))
.on('receipt', console.log);

> // see eth.getTransactionReceipt() for details

Note

When use the package ethereumjs-tx at the version of 2.0.0, if we don’t specify the parameter chain, it will use mainnet, so if you wan to use at the other network, you should add this parameter chain to specify.

sign¶

web3.eth.sign(dataToSign, address [, callback])

Signs data using a specific account. This account needs to be unlocked.

Parameters¶

String - Data to sign. If String it will be converted using web3.utils.utf8ToHex.
String|Number - Address to sign data with. Or an address or index of a local wallet in web3.eth.accounts.wallet.
Function - (optional) Optional callback, returns an error object as first parameter and the result as second.

Note

The 2. address parameter can also be an address or index from the web3.eth.accounts.wallet. It will then sign locally using the private key of this account.

Returns¶

Promise returns String - The signature.

Example¶

web3.eth.sign("Hello world", "0x11f4d0A3c12e86B4b5F39B213F7E19D048276DAe")
.then(console.log);
> "0x30755ed65396facf86c53e6217c52b4daebe72aa4941d89635409de4c9c7f9466d4e9aaec7977f05e923889b33c0d0dd27d7226b6e6f56ce737465c5cfd04be400"

// the below is the same
web3.eth.sign(web3.utils.utf8ToHex("Hello world"), "0x11f4d0A3c12e86B4b5F39B213F7E19D048276DAe")
.then(console.log);
> "0x30755ed65396facf86c53e6217c52b4daebe72aa4941d89635409de4c9c7f9466d4e9aaec7977f05e923889b33c0d0dd27d7226b6e6f56ce737465c5cfd04be400"

signTransaction¶

web3.eth.signTransaction(transactionObject, address [, callback])

Signs a transaction. This account needs to be unlocked.

Parameters¶

Object - The transaction data to sign web3.eth.sendTransaction() for more.
String - Address to sign transaction with.
Function - (optional) Optional callback, returns an error object as first parameter and the result as second.

Returns¶

Promise returns Object - The RLP encoded transaction. The raw property can be used to send the transaction using web3.eth.sendSignedTransaction.

Example¶

web3.eth.signTransaction({
    from: "0xEB014f8c8B418Db6b45774c326A0E64C78914dC0",
    gasPrice: "20000000000",
    gas: "21000",
    to: '0x3535353535353535353535353535353535353535',
    value: "1000000000000000000",
    data: ""
}).then(console.log);
> {
    raw: '0xf86c808504a817c800825208943535353535353535353535353535353535353535880de0b6b3a76400008025a04f4c17305743700648bc4f6cd3038ec6f6af0df73e31757007b7f59df7bee88da07e1941b264348e80c78c4027afc65a87b0a5e43e86742b8ca0823584c6788fd0',
    tx: {
        nonce: '0x0',
        gasPrice: '0x4a817c800',
        gas: '0x5208',
        to: '0x3535353535353535353535353535353535353535',
        value: '0xde0b6b3a7640000',
        input: '0x',
        v: '0x25',
        r: '0x4f4c17305743700648bc4f6cd3038ec6f6af0df73e31757007b7f59df7bee88d',
        s: '0x7e1941b264348e80c78c4027afc65a87b0a5e43e86742b8ca0823584c6788fd0',
        hash: '0xda3be87732110de6c1354c83770aae630ede9ac308d9f7b399ecfba23d923384'
    }
}

call¶

web3.eth.call(callObject [, defaultBlock] [, callback])

Executes a message call transaction, which is directly executed in the VM of the node, but never mined into the blockchain.

Parameters¶

Object - A transaction object see web3.eth.sendTransaction, with the difference that for calls the from property is optional as well.
Number|String|BN|BigNumber - (optional) If you pass this parameter it will not use the default block set with web3.eth.defaultBlock. Pre-defined block numbers as "latest", "earlist", "pending", and "genesis" can also be used.
Function - (optional) Optional callback, returns an error object as first parameter and the result as second.

Returns¶

Promise returns String: The returned data of the call, e.g. a smart contract functions return value.

Example¶

web3.eth.call({
    to: "0x11f4d0A3c12e86B4b5F39B213F7E19D048276DAe", // contract address
    data: "0xc6888fa10000000000000000000000000000000000000000000000000000000000000003"
})
.then(console.log);
> "0x000000000000000000000000000000000000000000000000000000000000000a"

estimateGas¶

web3.eth.estimateGas(callObject [, callback])

Executes a message call or transaction and returns the amount of the gas used.

Parameters¶

Object - A transaction object see web3.eth.sendTransaction, with the difference that for calls the from property is optional as well.
Function - (optional) Optional callback, returns an error object as first parameter and the result as second.

Returns¶

Promise returns Number - the used gas for the simulated call/transaction.

Example¶

web3.eth.estimateGas({
    to: "0x11f4d0A3c12e86B4b5F39B213F7E19D048276DAe",
    data: "0xc6888fa10000000000000000000000000000000000000000000000000000000000000003"
})
.then(console.log);
> "0x0000000000000000000000000000000000000000000000000000000000000015"

getPastLogs¶

web3.eth.getPastLogs(options [, callback])

Gets past logs, matching the given options.

Parameters¶

Object - The filter options as follows:

fromBlock - Number|String: The number of the earliest block ("latest" may be given to mean the most recent and "pending" currently mining, block). By default "latest".

toBlock - Number|String: The number of the latest block ("latest" may be given to mean the most recent and "pending" currently mining, block). By default "latest".

address - String|Array: An address or a list of addresses to only get logs from particular account(s).

topics - Array: An array of values which must each appear in the log entries. The order is important, if you want to leave topics out use null, e.g. [null, '0x12...']. You can also pass an array for each topic with options for that topic e.g. [null, ['option1', 'option2']]

Returns¶

Promise returns Array - Array of log objects.

The structure of the returned event Object in the Array looks as follows:

address - String: From which this event originated from.
data - String: The data containing non-indexed log parameter.
topics - Array: An array with max 4 32 Byte topics, topic 1-3 contains indexed parameters of the log.
logIndex - Number: Integer of the event index position in the block.
transactionIndex - Number: Integer of the transaction’s index position, the event was created in.
transactionHash 32 Bytes - String: Hash of the transaction this event was created in.
blockHash 32 Bytes - String: Hash of the block where this event was created in. null when its still pending.
blockNumber - Number: The block number where this log was created in. null when still pending.

Example¶

web3.eth.getPastLogs({
    address: "0x11f4d0A3c12e86B4b5F39B213F7E19D048276DAe",
    topics: ["0x033456732123ffff2342342dd12342434324234234fd234fd23fd4f23d4234"]
})
.then(console.log);

> [{
    data: '0x7f9fade1c0d57a7af66ab4ead79fade1c0d57a7af66ab4ead7c2c2eb7b11a91385',
    topics: ['0xfd43ade1c09fade1c0d57a7af66ab4ead7c2c2eb7b11a91ffdd57a7af66ab4ead7', '0x7f9fade1c0d57a7af66ab4ead79fade1c0d57a7af66ab4ead7c2c2eb7b11a91385']
    logIndex: 0,
    transactionIndex: 0,
    transactionHash: '0x7f9fade1c0d57a7af66ab4ead79fade1c0d57a7af66ab4ead7c2c2eb7b11a91385',
    blockHash: '0xfd43ade1c09fade1c0d57a7af66ab4ead7c2c2eb7b11a91ffdd57a7af66ab4ead7',
    blockNumber: 1234,
    address: '0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe'
},{...}]

getWork¶

web3.eth.getWork([callback])

Gets work for miners to mine on. Returns the hash of the current block, the seedHash, and the boundary condition to be met (“target”).

Parameters¶

Function - (optional) Optional callback, returns an error object as first parameter and the result as second.

Returns¶

Promise returns Array - the mining work with the following structure:

String 32 Bytes - at index 0: current block header pow-hash

String 32 Bytes - at index 1: the seed hash used for the DAG.

String 32 Bytes - at index 2: the boundary condition (“target”), 2^256 / difficulty.

Example¶

web3.eth.getWork()
.then(console.log);
> [
  "0x1234567890abcdef1234567890abcdef1234567890abcdef1234567890abcdef",
  "0x5EED00000000000000000000000000005EED0000000000000000000000000000",
  "0xd1ff1c01710000000000000000000000d1ff1c01710000000000000000000000"
]

submitWork¶

web3.eth.submitWork(nonce, powHash, digest, [callback])

Used for submitting a proof-of-work solution.

Parameters¶

String 8 Bytes: The nonce found (64 bits)
String 32 Bytes: The header’s pow-hash (256 bits)
String 32 Bytes: The mix digest (256 bits)
Function - (optional) Optional callback, returns an error object as first parameter and the result as second.

Returns¶

Promise returns Boolean - Returns TRUE if the provided solution is valid, otherwise false.

Example¶

web3.eth.submitWork([
    "0x0000000000000001",
    "0x1234567890abcdef1234567890abcdef1234567890abcdef1234567890abcdef",
    "0xD1FE5700000000000000000000000000D1FE5700000000000000000000000000"
])
.then(console.log);
> true

getChainId¶

web3.eth.getChainId([callback])

Returns the chain ID of the current connected node as described in the EIP-695.

Returns¶

Promise<Number> - Returns chain ID.

Example¶

web3.eth.getChainId().then(console.log);
> 61

getNodeInfo¶

web3.eth.getNodeInfo([callback])

Returns¶

Promise<String> - The current client version.

Example¶

web3.eth.getNodeInfo().then(console.log);
> "Mist/v0.9.3/darwin/go1.4.1"

web3.eth.Contract¶

The web3.eth.Contract object makes it easy to interact with smart contracts on the ethereum blockchain. When you create a new contract object you give it the json interface of the respective smart contract and web3 will auto convert all calls into low level ABI calls over RPC for you.

This allows you to interact with smart contracts as if they were JavaScript objects.

To use it standalone:

new contract¶

new web3.eth.Contract(jsonInterface[, address][, options])

Creates a new contract instance with all its methods and events defined in its json interface object.

Parameters¶

jsonInterface - Object: The json interface for the contract to instantiate
address - String (optional): The address of the smart contract to call.
options - Object (optional): The options of the contract. Some are used as fallbacks for calls and transactions:
- from - String: The address transactions should be made from.
- gasPrice - String: The gas price in wei to use for transactions.
- gas - Number: The maximum gas provided for a transaction (gas limit).
- data - String: The byte code of the contract. Used when the contract gets deployed.

Returns¶

Object: The contract instance with all its methods and events.

Example¶

var myContract = new web3.eth.Contract([...], '0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe', {
    from: '0x1234567890123456789012345678901234567891', // default from address
    gasPrice: '20000000000' // default gas price in wei, 20 gwei in this case
});

= Properties =¶

defaultAccount¶

web3.eth.Contract.defaultAccount
contract.defaultAccount // on contract instance

This default address is used as the default "from" property, if no "from" property is specified in for the following methods:

web3.eth.sendTransaction()
web3.eth.call()
new web3.eth.Contract() -> myContract.methods.myMethod().call()
new web3.eth.Contract() -> myContract.methods.myMethod().send()

Property¶

String - 20 Bytes: Any ethereum address. You should have the private key for that address in your node or keystore. (Default is undefined)

Example¶

web3.eth.defaultAccount;
> undefined

// set the default account
web3.eth.defaultAccount = '0x11f4d0A3c12e86B4b5F39B213F7E19D048276DAe';

defaultBlock¶

web3.eth.Contract.defaultBlock
contract.defaultBlock // on contract instance

The default block is used for certain methods. You can override it by passing in the defaultBlock as last parameter. The default value of it is “latest”.

Property¶

The default block parameters can be one of the following:

Number: A block number
"genesis" - String: The genesis block
"latest" - String: The latest block (current head of the blockchain)
"pending" - String: The currently mined block (including pending transactions)

Default is "latest"

Example¶

contract.defaultBlock;
> "latest"

// set the default block
contract.defaultBlock = 231;

defaultHardfork¶

contract.defaultHardfork

The default hardfork property is used for signing transactions locally.

Property¶

The default hardfork property can be one of the following:

"chainstart" - String
"homestead" - String
"dao" - String
"tangerineWhistle" - String
"spuriousDragon" - String
"byzantium" - String
"constantinople" - String
"petersburg" - String
"istanbul" - String

Default is "petersburg"

Example¶

contract.defaultHardfork;
> "petersburg"

// set the default block
contract.defaultHardfork = 'istanbul';

defaultChain¶

contract.defaultChain

The default chain property is used for signing transactions locally.

Property¶

The default chain property can be one of the following:

"mainnet" - String
"goerli" - String
"kovan" - String
"rinkeby" - String
"ropsten" - String

Default is "mainnet"

Example¶

contract.defaultChain;
> "mainnet"

// set the default chain
contract.defaultChain = 'goerli';

defaultCommon¶

contract.defaultCommon

The default common property is used for signing transactions locally.

Property¶

The default common property does contain the following Common object:

customChain - Object: The custom chain properties
- name - string: (optional) The name of the chain
- networkId - number: Network ID of the custom chain
- chainId - number: Chain ID of the custom chain
baseChain - string: (optional) mainnet, goerli, kovan, rinkeby, or ropsten
hardfork - string: (optional) chainstart, homestead, dao, tangerineWhistle, spuriousDragon, byzantium, constantinople, petersburg, or istanbul

Default is undefined.

Example¶

contract.defaultCommon;
> {customChain: {name: 'custom-network', chainId: 1, networkId: 1}, baseChain: 'mainnet', hardfork: 'petersburg'}

// set the default common
contract.defaultCommon = {customChain: {name: 'custom-network', chainId: 1, networkId: 1}, baseChain: 'mainnet', hardfork: 'petersburg'};

transactionBlockTimeout¶

web3.eth.Contract.transcationBlockTimeout
contract.transactionBlockTimeout // on contract instance

The transactionBlockTimeout will be used over a socket based connection. This option does define the amount of new blocks it should wait until the first confirmation happens. This means the PromiEvent rejects with a timeout error when the timeout got exceeded.

Returns¶

number: The current value of transactionBlockTimeout (default: 50)

transactionConfirmationBlocks¶

web3.eth.Contract.transactionConfirmationBlocks
contract.transactionConfirmationBlocks // on contract instance

This defines the number of blocks it requires until a transaction will be handled as confirmed.

Returns¶

number: The current value of transactionConfirmationBlocks (default: 24)

transactionPollingTimeout¶

web3.eth.Contract.transactionPollingTimeout
contract.transactionPollingTimeout // on contract instance

The transactionPollingTimeout will be used over a HTTP connection. This option defines the number of seconds Web3 will wait for a receipt which confirms that a transaction was mined by the network. NB: If this method times out, the transaction may still be pending.

Returns¶

number: The current value of transactionPollingTimeout (default: 750)

options¶

myContract.options

The options object for the contract instance. from, gas and gasPrice are used as fallback values when sending transactions.

Properties¶

Object - options:

address - String: The address where the contract is deployed. See options.address.
jsonInterface - Array: The json interface of the contract. See options.jsonInterface.
data - String: The byte code of the contract. Used when the contract gets deployed.
from - String: The address transactions should be made from.
gasPrice - String: The gas price in wei to use for transactions.
gas - Number: The maximum gas provided for a transaction (gas limit).

Example¶

myContract.options;
> {
    address: '0x1234567890123456789012345678901234567891',
    jsonInterface: [...],
    from: '0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe',
    gasPrice: '10000000000000',
    gas: 1000000
}

myContract.options.from = '0x1234567890123456789012345678901234567891'; // default from address
myContract.options.gasPrice = '20000000000000'; // default gas price in wei
myContract.options.gas = 5000000; // provide as fallback always 5M gas

options.address¶

myContract.options.address

The address used for this contract instance. All transactions generated by web3.js from this contract will contain this address as the “to”.

The address will be stored in lowercase.

Property¶

address - String|null: The address for this contract, or null if it’s not yet set.

Example¶

myContract.options.address;
> '0xde0b295669a9fd93d5f28d9ec85e40f4cb697bae'

// set a new address
myContract.options.address = '0x1234FFDD...';

options.jsonInterface¶

myContract.options.jsonInterface

The json interface object derived from the ABI of this contract.

Property¶

jsonInterface - Array: The json interface for this contract. Re-setting this will regenerate the methods and events of the contract instance.

Example¶

myContract.options.jsonInterface;
> [{
    "type":"function",
    "name":"foo",
    "inputs": [{"name":"a","type":"uint256"}],
    "outputs": [{"name":"b","type":"address"}]
},{
    "type":"event",
    "name":"Event",
    "inputs": [{"name":"a","type":"uint256","indexed":true},{"name":"b","type":"bytes32","indexed":false}],
}]

// set a new interface
myContract.options.jsonInterface = [...];

= Methods =¶

clone¶

myContract.clone()

Clones the current contract instance.

Parameters¶

none

Returns¶

Object: The new contract instance.

Example¶

var contract1 = new eth.Contract(abi, address, {gasPrice: '12345678', from: fromAddress});

var contract2 = contract1.clone();
contract2.options.address = address2;

(contract1.options.address !== contract2.options.address);
> true

deploy¶

myContract.deploy(options)

Call this function to deploy the contract to the blockchain. After successful deployment the promise will resolve with a new contract instance.

Parameters¶

options - Object: The options used for deployment.
- data - String: The byte code of the contract.
- arguments - Array (optional): The arguments which get passed to the constructor on deployment.

Returns¶

Object: The transaction object:

Array - arguments: The arguments passed to the method before. They can be changed.
Function - send: Will deploy the contract. The promise will resolve with the new contract instance, instead of the receipt!
Function - estimateGas: Will estimate the gas used for deploying.
Function - encodeABI: Encodes the ABI of the deployment, which is contract data + constructor parameters

For details to the methods see the documentation below.

Example¶

myContract.deploy({
    data: '0x12345...',
    arguments: [123, 'My String']
})
.send({
    from: '0x1234567890123456789012345678901234567891',
    gas: 1500000,
    gasPrice: '30000000000000'
}, function(error, transactionHash){ ... })
.on('error', function(error){ ... })
.on('transactionHash', function(transactionHash){ ... })
.on('receipt', function(receipt){
   console.log(receipt.contractAddress) // contains the new contract address
})
.on('confirmation', function(confirmationNumber, receipt){ ... })
.then(function(newContractInstance){
    console.log(newContractInstance.options.address) // instance with the new contract address
});


// When the data is already set as an option to the contract itself
myContract.options.data = '0x12345...';

myContract.deploy({
    arguments: [123, 'My String']
})
.send({
    from: '0x1234567890123456789012345678901234567891',
    gas: 1500000,
    gasPrice: '30000000000000'
})
.then(function(newContractInstance){
    console.log(newContractInstance.options.address) // instance with the new contract address
});


// Simply encoding
myContract.deploy({
    data: '0x12345...',
    arguments: [123, 'My String']
})
.encodeABI();
> '0x12345...0000012345678765432'


// Gas estimation
myContract.deploy({
    data: '0x12345...',
    arguments: [123, 'My String']
})
.estimateGas(function(err, gas){
    console.log(gas);
});

methods¶

myContract.methods.myMethod([param1[, param2[, ...]]])

Creates a transaction object for that method, which then can be called, send, estimated.

The methods of this smart contract are available through:

The name: myContract.methods.myMethod(123)
The name with parameters: myContract.methods['myMethod(uint256)'](123)
The signature: myContract.methods['0x58cf5f10'](123)

This allows calling functions with same name but different parameters from the JavaScript contract object.

Parameters¶

Parameters of any method depend on the smart contracts methods, defined in the JSON interface.

Returns¶

Object: The transaction object:

Array - arguments: The arguments passed to the method before. They can be changed.
Function - call: Will call the “constant” method and execute its smart contract method in the EVM without sending a transaction (Can’t alter the smart contract state).
Function - send: Will send a transaction to the smart contract and execute its method (Can alter the smart contract state).
Function - estimateGas: Will estimate the gas used when the method would be executed on chain.
Function - encodeABI: Encodes the ABI for this method. This can be send using a transaction, call the method or passing into another smart contracts method as argument.

For details to the methods see the documentation below.

Example¶

// calling a method

myContract.methods.myMethod(123).call({from: '0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe'}, function(error, result){
    ...
});

// or sending and using a promise
myContract.methods.myMethod(123).send({from: '0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe'})
.then(function(receipt){
    // receipt can also be a new contract instance, when coming from a "contract.deploy({...}).send()"
});

// or sending and using the events

myContract.methods.myMethod(123).send({from: '0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe'})
.on('transactionHash', function(hash){
    ...
})
.on('receipt', function(receipt){
    ...
})
.on('confirmation', function(confirmationNumber, receipt){
    ...
})
.on('error', function(error, receipt) {
    ...
});

methods.myMethod.call¶

myContract.methods.myMethod([param1[, param2[, ...]]]).call(options[, callback])

Will call a “constant” method and execute its smart contract method in the EVM without sending any transaction. Note calling can not alter the smart contract state.

Parameters¶

options - Object (optional): The options used for calling.
- from - String (optional): The address the call “transaction” should be made from.
- gasPrice - String (optional): The gas price in wei to use for this call “transaction”.
- gas - Number (optional): The maximum gas provided for this call “transaction” (gas limit).
callback - Function (optional): This callback will be fired with the result of the smart contract method execution as the second argument, or with an error object as the first argument.

Returns¶

Promise returns Mixed: The return value(s) of the smart contract method. If it returns a single value, it’s returned as is. If it has multiple return values they are returned as an object with properties and indices:

Example¶

// using the callback
myContract.methods.myMethod(123).call({from: '0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe'}, function(error, result){
    ...
});

// using the promise
myContract.methods.myMethod(123).call({from: '0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe'})
.then(function(result){
    ...
});


// MULTI-ARGUMENT RETURN:

// Solidity
contract MyContract {
    function myFunction() returns(uint256 myNumber, string myString) {
        return (23456, "Hello!%");
    }
}

// web3.js
var MyContract = new web3.eth.Contract(abi, address);
MyContract.methods.myFunction().call()
.then(console.log);
> Result {
    myNumber: '23456',
    myString: 'Hello!%',
    0: '23456', // these are here as fallbacks if the name is not know or given
    1: 'Hello!%'
}


// SINGLE-ARGUMENT RETURN:

// Solidity
contract MyContract {
    function myFunction() returns(string myString) {
        return "Hello!%";
    }
}

// web3.js
var MyContract = new web3.eth.Contract(abi, address);
MyContract.methods.myFunction().call()
.then(console.log);
> "Hello!%"

methods.myMethod.send¶

myContract.methods.myMethod([param1[, param2[, ...]]]).send(options[, callback])

Will send a transaction to the smart contract and execute its method. Note this can alter the smart contract state.

Parameters¶

options - Object: The options used for sending.
- from - String: The address the transaction should be sent from.
- gasPrice - String (optional): The gas price in wei to use for this transaction.
- gas - Number (optional): The maximum gas provided for this transaction (gas limit).
- value - ``Number|String|BN|BigNumber``(optional): The value transferred for the transaction in wei.
callback - Function (optional): This callback will be fired first with the “transactionHash”, or with an error object as the first argument.

Returns¶

The callback will return the 32 bytes transaction hash.

PromiEvent: A promise combined event emitter. Will be resolved when the transaction receipt is available, OR if this send() is called from a someContract.deploy(), then the promise will resolve with the new contract instance. Additionally the following events are available:

"transactionHash" returns String: is fired right after the transaction is sent and a transaction hash is available.
"receipt" returns Object: is fired when the transaction receipt is available. Receipts from contracts will have no logs property, but instead an events property with event names as keys and events as properties. See getPastEvents return values for details about the returned event object.
"confirmation" returns Number, Object: is fired for every confirmation up to the 24th confirmation. Receives the confirmation number as the first and the receipt as the second argument. Fired from confirmation 1 on, which is the block where it’s minded.
"error" returns Error and Object|undefined: Is fired if an error occurs during sending. If the transaction was rejected by the network with a receipt, the second parameter will be the receipt.

Example¶

// using the callback
myContract.methods.myMethod(123).send({from: '0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe'}, function(error, transactionHash){
    ...
});

// using the promise
myContract.methods.myMethod(123).send({from: '0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe'})
.then(function(receipt){
    // receipt can also be a new contract instance, when coming from a "contract.deploy({...}).send()"
});


// using the event emitter
myContract.methods.myMethod(123).send({from: '0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe'})
.on('transactionHash', function(hash){
    ...
})
.on('confirmation', function(confirmationNumber, receipt){
    ...
})
.on('receipt', function(receipt){
    // receipt example
    console.log(receipt);
    > {
        "transactionHash": "0x9fc76417374aa880d4449a1f7f31ec597f00b1f6f3dd2d66f4c9c6c445836d8b",
        "transactionIndex": 0,
        "blockHash": "0xef95f2f1ed3ca60b048b4bf67cde2195961e0bba6f70bcbea9a2c4e133e34b46",
        "blockNumber": 3,
        "contractAddress": "0x11f4d0A3c12e86B4b5F39B213F7E19D048276DAe",
        "cumulativeGasUsed": 314159,
        "gasUsed": 30234,
        "events": {
            "MyEvent": {
                returnValues: {
                    myIndexedParam: 20,
                    myOtherIndexedParam: '0x123456789...',
                    myNonIndexParam: 'My String'
                },
                raw: {
                    data: '0x7f9fade1c0d57a7af66ab4ead79fade1c0d57a7af66ab4ead7c2c2eb7b11a91385',
                    topics: ['0xfd43ade1c09fade1c0d57a7af66ab4ead7c2c2eb7b11a91ffdd57a7af66ab4ead7', '0x7f9fade1c0d57a7af66ab4ead79fade1c0d57a7af66ab4ead7c2c2eb7b11a91385']
                },
                event: 'MyEvent',
                signature: '0xfd43ade1c09fade1c0d57a7af66ab4ead7c2c2eb7b11a91ffdd57a7af66ab4ead7',
                logIndex: 0,
                transactionIndex: 0,
                transactionHash: '0x7f9fade1c0d57a7af66ab4ead79fade1c0d57a7af66ab4ead7c2c2eb7b11a91385',
                blockHash: '0xfd43ade1c09fade1c0d57a7af66ab4ead7c2c2eb7b11a91ffdd57a7af66ab4ead7',
                blockNumber: 1234,
                address: '0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe'
            },
            "MyOtherEvent": {
                ...
            },
            "MyMultipleEvent":[{...}, {...}] // If there are multiple of the same event, they will be in an array
        }
    }
})
.on('error', function(error, receipt) { // If the transaction was rejected by the network with a receipt, the second parameter will be the receipt.
    ...
});

methods.myMethod.estimateGas¶

myContract.methods.myMethod([param1[, param2[, ...]]]).estimateGas(options[, callback])

Will call estimate the gas a method execution will take when executed in the EVM without. The estimation can differ from the actual gas used when later sending a transaction, as the state of the smart contract can be different at that time.

Parameters¶

options - Object (optional): The options used for calling.
- from - String (optional): The address the call “transaction” should be made from.
- gas - Number (optional): The maximum gas provided for this call “transaction” (gas limit). Setting a specific value helps to detect out of gas errors. If all gas is used it will return the same number.
- value - ``Number|String|BN|BigNumber``(optional): The value transferred for the call “transaction” in wei.
callback - Function (optional): This callback will be fired with the result of the gas estimation as the second argument, or with an error object as the first argument.

Returns¶

Promise returns Number: The gas amount estimated.

Example¶

// using the callback
myContract.methods.myMethod(123).estimateGas({gas: 5000000}, function(error, gasAmount){
    if(gasAmount == 5000000)
        console.log('Method ran out of gas');
});

// using the promise
myContract.methods.myMethod(123).estimateGas({from: '0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe'})
.then(function(gasAmount){
    ...
})
.catch(function(error){
    ...
});

methods.myMethod.encodeABI¶

myContract.methods.myMethod([param1[, param2[, ...]]]).encodeABI()

Encodes the ABI for this method. This can be used to send a transaction, call a method, or pass it into another smart contracts method as arguments.

Parameters¶

none

Returns¶

String: The encoded ABI byte code to send via a transaction or call.

Example¶

myContract.methods.myMethod(123).encodeABI();
> '0x58cf5f1000000000000000000000000000000000000000000000000000000000000007B'

= Events =¶

once¶

myContract.once(event[, options], callback)

Subscribes to an event and unsubscribes immediately after the first event or error. Will only fire for a single event.

Parameters¶

event - String: The name of the event in the contract, or "allEvents" to get all events.
options - Object (optional): The options used for deployment.
- filter - Object (optional): Lets you filter events by indexed parameters, e.g. {filter: {myNumber: [12,13]}} means all events where “myNumber” is 12 or 13.
- topics - Array (optional): This allows you to manually set the topics for the event filter. If given the filter property and event signature, (topic[0]) will not be set automatically.
callback - Function: This callback will be fired for the first event as the second argument, or an error as the first argument. See getPastEvents return values for details about the event structure.

Returns¶

undefined

Example¶

myContract.once('MyEvent', {
    filter: {myIndexedParam: [20,23], myOtherIndexedParam: '0x123456789...'}, // Using an array means OR: e.g. 20 or 23
    fromBlock: 0
}, function(error, event){ console.log(event); });

// event output example
> {
    returnValues: {
        myIndexedParam: 20,
        myOtherIndexedParam: '0x123456789...',
        myNonIndexParam: 'My String'
    },
    raw: {
        data: '0x7f9fade1c0d57a7af66ab4ead79fade1c0d57a7af66ab4ead7c2c2eb7b11a91385',
        topics: ['0xfd43ade1c09fade1c0d57a7af66ab4ead7c2c2eb7b11a91ffdd57a7af66ab4ead7', '0x7f9fade1c0d57a7af66ab4ead79fade1c0d57a7af66ab4ead7c2c2eb7b11a91385']
    },
    event: 'MyEvent',
    signature: '0xfd43ade1c09fade1c0d57a7af66ab4ead7c2c2eb7b11a91ffdd57a7af66ab4ead7',
    logIndex: 0,
    transactionIndex: 0,
    transactionHash: '0x7f9fade1c0d57a7af66ab4ead79fade1c0d57a7af66ab4ead7c2c2eb7b11a91385',
    blockHash: '0xfd43ade1c09fade1c0d57a7af66ab4ead7c2c2eb7b11a91ffdd57a7af66ab4ead7',
    blockNumber: 1234,
    address: '0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe'
}

events¶

myContract.events.MyEvent([options][, callback])

Subscribe to an event

Parameters¶

options - Object (optional): The options used for deployment.
- filter - Object (optional): Let you filter events by indexed parameters, e.g. {filter: {myNumber: [12,13]}} means all events where “myNumber” is 12 or 13.
- fromBlock - Number|String|BN|BigNumber (optional): The block number (greater than or equal to) from which to get events on. Pre-defined block numbers as "latest", "earlist", "pending", and "genesis" can also be used.
- topics - Array (optional): This allows to manually set the topics for the event filter. If given the filter property and event signature, (topic[0]) will not be set automatically.
callback - Function (optional): This callback will be fired for each event as the second argument, or an error as the first argument.

Returns¶

EventEmitter: The event emitter has the following events:

"data" returns Object: Fires on each incoming event with the event object as argument.
"changed" returns Object: Fires on each event which was removed from the blockchain. The event will have the additional property "removed: true".
"error" returns Object: Fires when an error in the subscription occours.
"connected" returns String: Fires once after the subscription successfully connected. Returns the subscription id.

The structure of the returned event Object looks as follows:

event - String: The event name.
signature - String|Null: The event signature, null if it’s an anonymous event.
address - String: Address this event originated from.
returnValues - Object: The return values coming from the event, e.g. {myVar: 1, myVar2: '0x234...'}.
logIndex - Number: Integer of the event index position in the block.
transactionIndex - Number: Integer of the transaction’s index position the event was created in.
transactionHash 32 Bytes - String: Hash of the transaction this event was created in.
blockHash 32 Bytes - String: Hash of the block this event was created in. null when it’s still pending.
blockNumber - Number: The block number this log was created in. null when still pending.
raw.data - String: The data containing non-indexed log parameter.
raw.topics - Array: An array with max 4 32 Byte topics, topic 1-3 contains indexed parameters of the event.

Example¶

myContract.events.MyEvent({
    filter: {myIndexedParam: [20,23], myOtherIndexedParam: '0x123456789...'}, // Using an array means OR: e.g. 20 or 23
    fromBlock: 0
}, function(error, event){ console.log(event); })
.on("connected", function(subscriptionId){
    console.log(subscriptionId);
})
.on('data', function(event){
    console.log(event); // same results as the optional callback above
})
.on('changed', function(event){
    // remove event from local database
})
.on('error', function(error, receipt) { // If the transaction was rejected by the network with a receipt, the second parameter will be the receipt.
    ...
});

// event output example
> {
    returnValues: {
        myIndexedParam: 20,
        myOtherIndexedParam: '0x123456789...',
        myNonIndexParam: 'My String'
    },
    raw: {
        data: '0x7f9fade1c0d57a7af66ab4ead79fade1c0d57a7af66ab4ead7c2c2eb7b11a91385',
        topics: ['0xfd43ade1c09fade1c0d57a7af66ab4ead7c2c2eb7b11a91ffdd57a7af66ab4ead7', '0x7f9fade1c0d57a7af66ab4ead79fade1c0d57a7af66ab4ead7c2c2eb7b11a91385']
    },
    event: 'MyEvent',
    signature: '0xfd43ade1c09fade1c0d57a7af66ab4ead7c2c2eb7b11a91ffdd57a7af66ab4ead7',
    logIndex: 0,
    transactionIndex: 0,
    transactionHash: '0x7f9fade1c0d57a7af66ab4ead79fade1c0d57a7af66ab4ead7c2c2eb7b11a91385',
    blockHash: '0xfd43ade1c09fade1c0d57a7af66ab4ead7c2c2eb7b11a91ffdd57a7af66ab4ead7',
    blockNumber: 1234,
    address: '0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe'
}

events.allEvents¶

myContract.events.allEvents([options][, callback])

Same as events but receives all events from this smart contract. Optionally the filter property can filter those events.

getPastEvents¶

myContract.getPastEvents(event[, options][, callback])

Gets past events for this contract.

Parameters¶

event - String: The name of the event in the contract, or "allEvents" to get all events.
options - Object (optional): The options used for deployment.
- filter - Object (optional): Lets you filter events by indexed parameters, e.g. {filter: {myNumber: [12,13]}} means all events where “myNumber” is 12 or 13.
- fromBlock - Number|String|BN|BigNumber (optional): The block number (greater than or equal to) from which to get events on. Pre-defined block numbers as "latest", "earlist", "pending", and "genesis" can also be used.
- toBlock - Number|String|BN|BigNumber (optional): The block number (less than or equal to) to get events up to (Defaults to "latest"). Pre-defined block numbers as "latest", "earlist", "pending", and "genesis" can also be used.
- topics - Array (optional): This allows manually setting the topics for the event filter. If given the filter property and event signature, (topic[0]) will not be set automatically.
callback - Function (optional): This callback will be fired with an array of event logs as the second argument, or an error as the first argument.

Returns¶

Promise returns Array: An array with the past event Objects, matching the given event name and filter.

For the structure of a returned event Object see getPastEvents return values.

Example¶

myContract.getPastEvents('MyEvent', {
    filter: {myIndexedParam: [20,23], myOtherIndexedParam: '0x123456789...'}, // Using an array means OR: e.g. 20 or 23
    fromBlock: 0,
    toBlock: 'latest'
}, function(error, events){ console.log(events); })
.then(function(events){
    console.log(events) // same results as the optional callback above
});

> [{
    returnValues: {
        myIndexedParam: 20,
        myOtherIndexedParam: '0x123456789...',
        myNonIndexParam: 'My String'
    },
    raw: {
        data: '0x7f9fade1c0d57a7af66ab4ead79fade1c0d57a7af66ab4ead7c2c2eb7b11a91385',
        topics: ['0xfd43ade1c09fade1c0d57a7af66ab4ead7c2c2eb7b11a91ffdd57a7af66ab4ead7', '0x7f9fade1c0d57a7af66ab4ead79fade1c0d57a7af66ab4ead7c2c2eb7b11a91385']
    },
    event: 'MyEvent',
    signature: '0xfd43ade1c09fade1c0d57a7af66ab4ead7c2c2eb7b11a91ffdd57a7af66ab4ead7',
    logIndex: 0,
    transactionIndex: 0,
    transactionHash: '0x7f9fade1c0d57a7af66ab4ead79fade1c0d57a7af66ab4ead7c2c2eb7b11a91385',
    blockHash: '0xfd43ade1c09fade1c0d57a7af66ab4ead7c2c2eb7b11a91ffdd57a7af66ab4ead7',
    blockNumber: 1234,
    address: '0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe'
},{
    ...
}]

web3.eth.accounts¶

The web3.eth.accounts contains functions to generate Ethereum accounts and sign transactions and data.

Note

This package has NOT been audited and might potentially be unsafe. Take precautions to clear memory properly, store the private keys safely, and test transaction receiving and sending functionality properly before using in production!

To use this package standalone use:

var Accounts = require('web3-eth-accounts');

// Passing in the eth or web3 package is necessary to allow retrieving chainId, gasPrice and nonce automatically
// for accounts.signTransaction().
var accounts = new Accounts('ws://localhost:8546');

create¶

web3.eth.accounts.create([entropy]);

Generates an account object with private key and public key.

Parameters¶

entropy - String (optional): A random string to increase entropy. If given it should be at least 32 characters. If none is given a random string will be generated using randomhex.

Returns¶

Object - The account object with the following structure:

address - string: The account address.

privateKey - string: The accounts private key. This should never be shared or stored unencrypted in localstorage! Also make sure to null the memory after usage.

signTransaction(tx [, callback]) - Function: The function to sign transactions. See web3.eth.accounts.signTransaction() for more.

sign(data) - Function: The function to sign transactions. See web3.eth.accounts.sign() for more.

Example¶

web3.eth.accounts.create();
> {
    address: "0xb8CE9ab6943e0eCED004cDe8e3bBed6568B2Fa01",
    privateKey: "0x348ce564d427a3311b6536bbcff9390d69395b06ed6c486954e971d960fe8709",
    signTransaction: function(tx){...},
    sign: function(data){...},
    encrypt: function(password){...}
}

web3.eth.accounts.create('2435@#@#@±±±±!!!!678543213456764321§34567543213456785432134567');
> {
    address: "0xF2CD2AA0c7926743B1D4310b2BC984a0a453c3d4",
    privateKey: "0xd7325de5c2c1cf0009fac77d3d04a9c004b038883446b065871bc3e831dcd098",
    signTransaction: function(tx){...},
    sign: function(data){...},
    encrypt: function(password){...}
}

web3.eth.accounts.create(web3.utils.randomHex(32));
> {
    address: "0xe78150FaCD36E8EB00291e251424a0515AA1FF05",
    privateKey: "0xcc505ee6067fba3f6fc2050643379e190e087aeffe5d958ab9f2f3ed3800fa4e",
    signTransaction: function(tx){...},
    sign: function(data){...},
    encrypt: function(password){...}
}

privateKeyToAccount¶

web3.eth.accounts.privateKeyToAccount(privateKey);

Creates an account object from a private key.

Parameters¶

privateKey - String: The private key to convert.

Returns¶

Object - The account object with the structure seen here.

Example¶

web3.eth.accounts.privateKeyToAccount('0x348ce564d427a3311b6536bbcff9390d69395b06ed6c486954e971d960fe8709');
> {
    address: '0xb8CE9ab6943e0eCED004cDe8e3bBed6568B2Fa01',
    privateKey: '0x348ce564d427a3311b6536bbcff9390d69395b06ed6c486954e971d960fe8709',
    signTransaction: function(tx){...},
    sign: function(data){...},
    encrypt: function(password){...}
}

signTransaction¶

web3.eth.accounts.signTransaction(tx, privateKey [, callback]);

Signs an Ethereum transaction with a given private key.

Parameters¶

tx - Object: The transaction object as follows:
- nonce - String: (optional) The nonce to use when signing this transaction. Default will use web3.eth.getTransactionCount().
- chainId - String: (optional) The chain id to use when signing this transaction. Default will use web3.eth.net.getId().
- to - String: (optional) The recevier of the transaction, can be empty when deploying a contract.
- data - String: (optional) The call data of the transaction, can be empty for simple value transfers.
- value - String: (optional) The value of the transaction in wei.
- gasPrice - String: (optional) The gas price set by this transaction, if empty, it will use web3.eth.gasPrice()
- gas - String: The gas provided by the transaction.
- chain - String: (optional) Defaults to mainnet.
- hardfork - String: (optional) Defaults to petersburg.
- common - Object: (optional) The common object
  
  customChain - Object: The custom chain properties
  
  name - string: (optional) The name of the chain
  
  networkId - number: Network ID of the custom chain
  
  chainId - number: Chain ID of the custom chain
  
  baseChain - string: (optional) mainnet, goerli, kovan, rinkeby, or ropsten
  
  hardfork - string: (optional) chainstart, homestead, dao, tangerineWhistle, spuriousDragon, byzantium, constantinople, petersburg, or istanbul
privateKey - String: The private key to sign with.
callback - Function: (optional) Optional callback, returns an error object as first parameter and the result as second.

Returns¶

Promise returning Object: The signed data RLP encoded transaction, or if returnSignature is true the signature values as follows:

messageHash - String: The hash of the given message.
r - String: First 32 bytes of the signature
s - String: Next 32 bytes of the signature
v - String: Recovery value + 27
rawTransaction - String: The RLP encoded transaction, ready to be send using web3.eth.sendSignedTransaction.
transactionHash - String: The transaction hash for the RLP encoded transaction.

Example¶

web3.eth.accounts.signTransaction({
    to: '0xF0109fC8DF283027b6285cc889F5aA624EaC1F55',
    value: '1000000000',
    gas: 2000000
}, '0x4c0883a69102937d6231471b5dbb6204fe5129617082792ae468d01a3f362318')
.then(console.log);
> {
    messageHash: '0x31c2f03766b36f0346a850e78d4f7db2d9f4d7d54d5f272a750ba44271e370b1',
    v: '0x25',
    r: '0xc9cf86333bcb065d140032ecaab5d9281bde80f21b9687b3e94161de42d51895',
    s: '0x727a108a0b8d101465414033c3f705a9c7b826e596766046ee1183dbc8aeaa68',
    rawTransaction: '0xf869808504e3b29200831e848094f0109fc8df283027b6285cc889f5aa624eac1f55843b9aca008025a0c9cf86333bcb065d140032ecaab5d9281bde80f21b9687b3e94161de42d51895a0727a108a0b8d101465414033c3f705a9c7b826e596766046ee1183dbc8aeaa68'
    transactionHash: '0xde8db924885b0803d2edc335f745b2b8750c8848744905684c20b987443a9593'
}

web3.eth.accounts.signTransaction({
    to: '0xF0109fC8DF283027b6285cc889F5aA624EaC1F55',
    value: '1000000000',
    gas: 2000000,
    gasPrice: '234567897654321',
    nonce: 0,
    chainId: 1
}, '0x4c0883a69102937d6231471b5dbb6204fe5129617082792ae468d01a3f362318')
.then(console.log);
> {
    messageHash: '0x6893a6ee8df79b0f5d64a180cd1ef35d030f3e296a5361cf04d02ce720d32ec5',
    r: '0x9ebb6ca057a0535d6186462bc0b465b561c94a295bdb0621fc19208ab149a9c',
    s: '0x440ffd775ce91a833ab410777204d5341a6f9fa91216a6f3ee2c051fea6a0428',
    v: '0x25',
    rawTransaction: '0xf86a8086d55698372431831e848094f0109fc8df283027b6285cc889f5aa624eac1f55843b9aca008025a009ebb6ca057a0535d6186462bc0b465b561c94a295bdb0621fc19208ab149a9ca0440ffd775ce91a833ab410777204d5341a6f9fa91216a6f3ee2c051fea6a0428'
    transactionHash: '0xd8f64a42b57be0d565f385378db2f6bf324ce14a594afc05de90436e9ce01f60'
}

// or with a common
web3.eth.accounts.signTransaction({
    to: '0xF0109fC8DF283027b6285cc889F5aA624EaC1F55',
    value: '1000000000',
    gas: 2000000
    common: {
      baseChain: 'mainnet',
      hardfork: 'petersburg',
      customChain: {
        name: 'custom-chain',
        chainId: 1,
        networkId: 1
      }
    }
}, '0x4c0883a69102937d6231471b5dbb6204fe5129617082792ae468d01a3f362318')
.then(console.log);

recoverTransaction¶

web3.eth.accounts.recoverTransaction(rawTransaction);

Recovers the Ethereum address which was used to sign the given RLP encoded transaction.

Parameters¶

signature - String: The RLP encoded transaction.

Returns¶

String: The Ethereum address used to sign this transaction.

Example¶

web3.eth.accounts.recoverTransaction('0xf86180808401ef364594f0109fc8df283027b6285cc889f5aa624eac1f5580801ca031573280d608f75137e33fc14655f097867d691d5c4c44ebe5ae186070ac3d5ea0524410802cdc025034daefcdfa08e7d2ee3f0b9d9ae184b2001fe0aff07603d9');
> "0xF0109fC8DF283027b6285cc889F5aA624EaC1F55"

hashMessage¶

web3.eth.accounts.hashMessage(message);

Hashes the given message to be passed web3.eth.accounts.recover() function. The data will be UTF-8 HEX decoded and enveloped as follows: "\x19Ethereum Signed Message:\n" + message.length + message and hashed using keccak256.

Parameters¶

message - String: A message to hash, if its HEX it will be UTF8 decoded before.

Returns¶

String: The hashed message

Example¶

web3.eth.accounts.hashMessage("Hello World")
> "0xa1de988600a42c4b4ab089b619297c17d53cffae5d5120d82d8a92d0bb3b78f2"

// the below results in the same hash
web3.eth.accounts.hashMessage(web3.utils.utf8ToHex("Hello World"))
> "0xa1de988600a42c4b4ab089b619297c17d53cffae5d5120d82d8a92d0bb3b78f2"

sign¶

web3.eth.accounts.sign(data, privateKey);

Signs arbitrary data.

Parameters¶

data - String: The data to sign.
privateKey - String: The private key to sign with.

Note

The value passed as the data parameter will be UTF-8 HEX decoded and wrapped as follows: "\x19Ethereum Signed Message:\n" + message.length + message.

Returns¶

Object: The signature object

message - String: The the given message.
messageHash - String: The hash of the given message.
r - String: First 32 bytes of the signature
s - String: Next 32 bytes of the signature
v - String: Recovery value + 27

Example¶

web3.eth.accounts.sign('Some data', '0x4c0883a69102937d6231471b5dbb6204fe5129617082792ae468d01a3f362318');
> {
    message: 'Some data',
    messageHash: '0x1da44b586eb0729ff70a73c326926f6ed5a25f5b056e7f47fbc6e58d86871655',
    v: '0x1c',
    r: '0xb91467e570a6466aa9e9876cbcd013baba02900b8979d43fe208a4a4f339f5fd',
    s: '0x6007e74cd82e037b800186422fc2da167c747ef045e5d18a5f5d4300f8e1a029',
    signature: '0xb91467e570a6466aa9e9876cbcd013baba02900b8979d43fe208a4a4f339f5fd6007e74cd82e037b800186422fc2da167c747ef045e5d18a5f5d4300f8e1a0291c'
}

recover¶

web3.eth.accounts.recover(signatureObject);
web3.eth.accounts.recover(message, signature [, preFixed]);
web3.eth.accounts.recover(message, v, r, s [, preFixed]);

Recovers the Ethereum address which was used to sign the given data.

Parameters¶

message|signatureObject - String|Object: Either signed message or hash, or the signature object as following values:
- messageHash - String: The hash of the given message already prefixed with "\x19Ethereum Signed Message:\n" + message.length + message.
- r - String: First 32 bytes of the signature
- s - String: Next 32 bytes of the signature
- v - String: Recovery value + 27
signature - String: The raw RLP encoded signature, OR parameter 2-4 as v, r, s values.
preFixed - Boolean (optional, default: false): If the last parameter is true, the given message will NOT automatically be prefixed with "\x19Ethereum Signed Message:\n" + message.length + message, and assumed to be already prefixed.

Returns¶

String: The Ethereum address used to sign this data.

Example¶

web3.eth.accounts.recover({
    messageHash: '0x1da44b586eb0729ff70a73c326926f6ed5a25f5b056e7f47fbc6e58d86871655',
    v: '0x1c',
    r: '0xb91467e570a6466aa9e9876cbcd013baba02900b8979d43fe208a4a4f339f5fd',
    s: '0x6007e74cd82e037b800186422fc2da167c747ef045e5d18a5f5d4300f8e1a029'
})
> "0x2c7536E3605D9C16a7a3D7b1898e529396a65c23"

// message, signature
web3.eth.accounts.recover('Some data', '0xb91467e570a6466aa9e9876cbcd013baba02900b8979d43fe208a4a4f339f5fd6007e74cd82e037b800186422fc2da167c747ef045e5d18a5f5d4300f8e1a0291c');
> "0x2c7536E3605D9C16a7a3D7b1898e529396a65c23"

// message, v, r, s
web3.eth.accounts.recover('Some data', '0x1c', '0xb91467e570a6466aa9e9876cbcd013baba02900b8979d43fe208a4a4f339f5fd', '0x6007e74cd82e037b800186422fc2da167c747ef045e5d18a5f5d4300f8e1a029');
> "0x2c7536E3605D9C16a7a3D7b1898e529396a65c23"

encrypt¶

web3.eth.accounts.encrypt(privateKey, password);

Encrypts a private key to the web3 keystore v3 standard.

Parameters¶

privateKey - String: The private key to encrypt.
password - String: The password used for encryption.

Returns¶

Object: The encrypted keystore v3 JSON.

Example¶

web3.eth.accounts.encrypt('0x4c0883a69102937d6231471b5dbb6204fe5129617082792ae468d01a3f362318', 'test!')
> {
    version: 3,
    id: '04e9bcbb-96fa-497b-94d1-14df4cd20af6',
    address: '2c7536e3605d9c16a7a3d7b1898e529396a65c23',
    crypto: {
        ciphertext: 'a1c25da3ecde4e6a24f3697251dd15d6208520efc84ad97397e906e6df24d251',
        cipherparams: { iv: '2885df2b63f7ef247d753c82fa20038a' },
        cipher: 'aes-128-ctr',
        kdf: 'scrypt',
        kdfparams: {
            dklen: 32,
            salt: '4531b3c174cc3ff32a6a7a85d6761b410db674807b2d216d022318ceee50be10',
            n: 262144,
            r: 8,
            p: 1
        },
        mac: 'b8b010fff37f9ae5559a352a185e86f9b9c1d7f7a9f1bd4e82a5dd35468fc7f6'
    }
}

decrypt¶

web3.eth.accounts.decrypt(keystoreJsonV3, password);

Decrypts a keystore v3 JSON, and creates the account.

Parameters¶

encryptedPrivateKey - String: The encrypted private key to decrypt.
password - String: The password used for encryption.

Returns¶

Object: The decrypted account.

Example¶

web3.eth.accounts.decrypt({
    version: 3,
    id: '04e9bcbb-96fa-497b-94d1-14df4cd20af6',
    address: '2c7536e3605d9c16a7a3d7b1898e529396a65c23',
    crypto: {
        ciphertext: 'a1c25da3ecde4e6a24f3697251dd15d6208520efc84ad97397e906e6df24d251',
        cipherparams: { iv: '2885df2b63f7ef247d753c82fa20038a' },
        cipher: 'aes-128-ctr',
        kdf: 'scrypt',
        kdfparams: {
            dklen: 32,
            salt: '4531b3c174cc3ff32a6a7a85d6761b410db674807b2d216d022318ceee50be10',
            n: 262144,
            r: 8,
            p: 1
        },
        mac: 'b8b010fff37f9ae5559a352a185e86f9b9c1d7f7a9f1bd4e82a5dd35468fc7f6'
    }
}, 'test!');
> {
    address: "0x2c7536E3605D9C16a7a3D7b1898e529396a65c23",
    privateKey: "0x4c0883a69102937d6231471b5dbb6204fe5129617082792ae468d01a3f362318",
    signTransaction: function(tx){...},
    sign: function(data){...},
    encrypt: function(password){...}
}

wallet¶

web3.eth.accounts.wallet;

Contains an in memory wallet with multiple accounts. These accounts can be used when using web3.eth.sendTransaction().

Example¶

web3.eth.accounts.wallet;
> Wallet {
    0: {...}, // account by index
    "0xF0109fC8DF283027b6285cc889F5aA624EaC1F55": {...},  // same account by address
    "0xf0109fc8df283027b6285cc889f5aa624eac1f55": {...},  // same account by address lowercase
    1: {...},
    "0xD0122fC8DF283027b6285cc889F5aA624EaC1d23": {...},
    "0xd0122fc8df283027b6285cc889f5aa624eac1d23": {...},

    add: function(){},
    remove: function(){},
    save: function(){},
    load: function(){},
    clear: function(){},

    length: 2,
}

wallet.create¶

web3.eth.accounts.wallet.create(numberOfAccounts [, entropy]);

Generates one or more accounts in the wallet. If wallets already exist they will not be overridden.

Parameters¶

numberOfAccounts - Number: Number of accounts to create. Leave empty to create an empty wallet.
entropy - String (optional): A string with random characters as additional entropy when generating accounts. If given it should be at least 32 characters.

Returns¶

Object: The wallet object.

Example¶

web3.eth.accounts.wallet.create(2, '54674321§3456764321§345674321§3453647544±±±§±±±!!!43534534534534');
> Wallet {
    0: {...},
    "0xF0109fC8DF283027b6285cc889F5aA624EaC1F55": {...},
    "0xf0109fc8df283027b6285cc889f5aa624eac1f55": {...},
    ...
}

wallet.add¶

web3.eth.accounts.wallet.add(account);

Adds an account using a private key or account object to the wallet.

Parameters¶

account - String|Object: A private key or account object created with web3.eth.accounts.create().

Returns¶

Object: The added account.

Example¶

web3.eth.accounts.wallet.add('0x4c0883a69102937d6231471b5dbb6204fe5129617082792ae468d01a3f362318');
> {
    index: 0,
    address: '0x2c7536E3605D9C16a7a3D7b1898e529396a65c23',
    privateKey: '0x4c0883a69102937d6231471b5dbb6204fe5129617082792ae468d01a3f362318',
    signTransaction: function(tx){...},
    sign: function(data){...},
    encrypt: function(password){...}
}

web3.eth.accounts.wallet.add({
    privateKey: '0x348ce564d427a3311b6536bbcff9390d69395b06ed6c486954e971d960fe8709',
    address: '0xb8CE9ab6943e0eCED004cDe8e3bBed6568B2Fa01'
});
> {
    index: 0,
    address: '0xb8CE9ab6943e0eCED004cDe8e3bBed6568B2Fa01',
    privateKey: '0x348ce564d427a3311b6536bbcff9390d69395b06ed6c486954e971d960fe8709',
    signTransaction: function(tx){...},
    sign: function(data){...},
    encrypt: function(password){...}
}

wallet.remove¶

web3.eth.accounts.wallet.remove(account);

Removes an account from the wallet.

Parameters¶

account - String|Number: The account address, or index in the wallet.

Returns¶

Boolean: true if the wallet was removed. false if it couldn’t be found.

Example¶

web3.eth.accounts.wallet;
> Wallet {
    0: {...},
    "0xF0109fC8DF283027b6285cc889F5aA624EaC1F55": {...}
    1: {...},
    "0xb8CE9ab6943e0eCED004cDe8e3bBed6568B2Fa01": {...}
    ...
}

web3.eth.accounts.wallet.remove('0xF0109fC8DF283027b6285cc889F5aA624EaC1F55');
> true

web3.eth.accounts.wallet.remove(3);
> false

wallet.clear¶

web3.eth.accounts.wallet.clear();

Securely empties the wallet and removes all its accounts.

Parameters¶

none

Returns¶

Object: The wallet object.

Example¶

web3.eth.accounts.wallet.clear();
> Wallet {
    add: function(){},
    remove: function(){},
    save: function(){},
    load: function(){},
    clear: function(){},

    length: 0
}

wallet.encrypt¶

web3.eth.accounts.wallet.encrypt(password);

Encrypts all wallet accounts to an array of encrypted keystore v3 objects.

Parameters¶

password - String: The password which will be used for encryption.

Returns¶

Array: The encrypted keystore v3.

Example¶

web3.eth.accounts.wallet.encrypt('test');
> [ { version: 3,
    id: 'dcf8ab05-a314-4e37-b972-bf9b86f91372',
    address: '06f702337909c06c82b09b7a22f0a2f0855d1f68',
    crypto:
     { ciphertext: '0de804dc63940820f6b3334e5a4bfc8214e27fb30bb7e9b7b74b25cd7eb5c604',
       cipherparams: [Object],
       cipher: 'aes-128-ctr',
       kdf: 'scrypt',
       kdfparams: [Object],
       mac: 'b2aac1485bd6ee1928665642bf8eae9ddfbc039c3a673658933d320bac6952e3' } },
  { version: 3,
    id: '9e1c7d24-b919-4428-b10e-0f3ef79f7cf0',
    address: 'b5d89661b59a9af0b34f58d19138baa2de48baaf',
    crypto:
     { ciphertext: 'd705ebed2a136d9e4db7e5ae70ed1f69d6a57370d5fbe06281eb07615f404410',
       cipherparams: [Object],
       cipher: 'aes-128-ctr',
       kdf: 'scrypt',
       kdfparams: [Object],
       mac: 'af9eca5eb01b0f70e909f824f0e7cdb90c350a802f04a9f6afe056602b92272b' } }
]

wallet.decrypt¶

web3.eth.accounts.wallet.decrypt(keystoreArray, password);

Decrypts keystore v3 objects.

Parameters¶

keystoreArray - Array: The encrypted keystore v3 objects to decrypt.
password - String: The password which will be used for encryption.

Returns¶

Object: The wallet object.

Example¶

web3.eth.accounts.wallet.decrypt([
  { version: 3,
  id: '83191a81-aaca-451f-b63d-0c5f3b849289',
  address: '06f702337909c06c82b09b7a22f0a2f0855d1f68',
  crypto:
   { ciphertext: '7d34deae112841fba86e3e6cf08f5398dda323a8e4d29332621534e2c4069e8d',
     cipherparams: { iv: '497f4d26997a84d570778eae874b2333' },
     cipher: 'aes-128-ctr',
     kdf: 'scrypt',
     kdfparams:
      { dklen: 32,
        salt: '208dd732a27aa4803bb760228dff18515d5313fd085bbce60594a3919ae2d88d',
        n: 262144,
        r: 8,
        p: 1 },
     mac: '0062a853de302513c57bfe3108ab493733034bf3cb313326f42cf26ea2619cf9' } },
   { version: 3,
  id: '7d6b91fa-3611-407b-b16b-396efb28f97e',
  address: 'b5d89661b59a9af0b34f58d19138baa2de48baaf',
  crypto:
   { ciphertext: 'cb9712d1982ff89f571fa5dbef447f14b7e5f142232bd2a913aac833730eeb43',
     cipherparams: { iv: '8cccb91cb84e435437f7282ec2ffd2db' },
     cipher: 'aes-128-ctr',
     kdf: 'scrypt',
     kdfparams:
      { dklen: 32,
        salt: '08ba6736363c5586434cd5b895e6fe41ea7db4785bd9b901dedce77a1514e8b8',
        n: 262144,
        r: 8,
        p: 1 },
     mac: 'd2eb068b37e2df55f56fa97a2bf4f55e072bef0dd703bfd917717d9dc54510f0' } }
], 'test');
> Wallet {
    0: {...},
    1: {...},
    "0xF0109fC8DF283027b6285cc889F5aA624EaC1F55": {...},
    "0xD0122fC8DF283027b6285cc889F5aA624EaC1d23": {...}
    ...
}

wallet.save¶

web3.eth.accounts.wallet.save(password [, keyName]);

Stores the wallet encrypted and as string in local storage.

Note

Browser only.

Parameters¶

password - String: The password to encrypt the wallet.
keyName - String: (optional) The key used for the local storage position, defaults to "web3js_wallet".

Returns¶

Boolean

Example¶

web3.eth.accounts.wallet.save('test#!$');
> true

wallet.load¶

web3.eth.accounts.wallet.load(password [, keyName]);

Loads a wallet from local storage and decrypts it.

Note

Browser only.

Parameters¶

password - String: The password to decrypt the wallet.
keyName - String: (optional) The key used for the localstorage position, defaults to "web3js_wallet".

Returns¶

Object: The wallet object.

Example¶

web3.eth.accounts.wallet.load('test#!$', 'myWalletKey');
> Wallet {
    0: {...},
    1: {...},
    "0xF0109fC8DF283027b6285cc889F5aA624EaC1F55": {...},
    "0xD0122fC8DF283027b6285cc889F5aA624EaC1d23": {...}
    ...
}

web3.eth.personal¶

The web3-eth-personal package allows you to interact with the Ethereum node’s accounts.

Note

Many of these functions send sensitive information, like password. Never call these functions over a unsecured Websocket or HTTP provider, as your password will be sent in plain text!

var Personal = require('web3-eth-personal');

// "Personal.providers.givenProvider" will be set if in an Ethereum supported browser.
var personal = new Personal(Personal.givenProvider || 'ws://some.local-or-remote.node:8546');

// or using the web3 umbrella package

var Web3 = require('web3');
var web3 = new Web3(Web3.givenProvider || 'ws://some.local-or-remote.node:8546');

// -> web3.eth.personal

setProvider¶

web3.setProvider(myProvider)
web3.eth.setProvider(myProvider)
web3.shh.setProvider(myProvider)
web3.bzz.setProvider(myProvider)
...

Will change the provider for its module.

Note

When called on the umbrella package web3 it will also set the provider for all sub modules web3.eth, web3.shh, etc EXCEPT web3.bzz which needs a separate provider at all times.

Parameters¶

Object - myProvider: a valid provider.

Returns¶

Boolean

Example¶

var Web3 = require('web3');
var web3 = new Web3('http://localhost:8545');
// or
var web3 = new Web3(new Web3.providers.HttpProvider('http://localhost:8545'));

// change provider
web3.setProvider('ws://localhost:8546');
// or
web3.setProvider(new Web3.providers.WebsocketProvider('ws://localhost:8546'));

// Using the IPC provider in node.js
var net = require('net');
var web3 = new Web3('/Users/myuser/Library/Ethereum/geth.ipc', net); // mac os path
// or
var web3 = new Web3(new Web3.providers.IpcProvider('/Users/myuser/Library/Ethereum/geth.ipc', net)); // mac os path
// on windows the path is: "\\\\.\\pipe\\geth.ipc"
// on linux the path is: "/users/myuser/.ethereum/geth.ipc"

providers¶

web3.providers
web3.eth.providers
web3.shh.providers
web3.bzz.providers
...

Contains the current available providers.

Value¶

Object with the following providers:

Object - HttpProvider: The HTTP provider is deprecated, as it won’t work for subscriptions.

Object - WebsocketProvider: The Websocket provider is the standard for usage in legacy browsers.

Object - IpcProvider: The IPC provider is used node.js dapps when running a local node. Gives the most secure connection.

Example¶

var Web3 = require('web3');
// use the given Provider, e.g in Mist, or instantiate a new websocket provider
var web3 = new Web3(Web3.givenProvider || 'ws://remotenode.com:8546');
// or
var web3 = new Web3(Web3.givenProvider || new Web3.providers.WebsocketProvider('ws://remotenode.com:8546'));

// Using the IPC provider in node.js
var net = require('net');

var web3 = new Web3('/Users/myuser/Library/Ethereum/geth.ipc', net); // mac os path
// or
var web3 = new Web3(new Web3.providers.IpcProvider('/Users/myuser/Library/Ethereum/geth.ipc', net)); // mac os path
// on windows the path is: "\\\\.\\pipe\\geth.ipc"
// on linux the path is: "/users/myuser/.ethereum/geth.ipc"

givenProvider¶

web3.givenProvider
web3.eth.givenProvider
web3.shh.givenProvider
web3.bzz.givenProvider
...

When using web3.js in an Ethereum compatible browser, it will set with the current native provider by that browser. Will return the given provider by the (browser) environment, otherwise null.

Returns¶

Object: The given provider set or null;

Example¶

currentProvider¶

web3.currentProvider
web3.eth.currentProvider
web3.shh.currentProvider
web3.bzz.currentProvider
...

Will return the current provider, otherwise null.

Returns¶

Object: The current provider set or null;

Example¶

BatchRequest¶

new web3.BatchRequest()
new web3.eth.BatchRequest()
new web3.shh.BatchRequest()
new web3.bzz.BatchRequest()

Class to create and execute batch requests.

Parameters¶

none

Returns¶

Object: With the following methods:

add(request): To add a request object to the batch call.

execute(): Will execute the batch request.

Example¶

var contract = new web3.eth.Contract(abi, address);

var batch = new web3.BatchRequest();
batch.add(web3.eth.getBalance.request('0x0000000000000000000000000000000000000000', 'latest', callback));
batch.add(contract.methods.balance(address).call.request({from: '0x0000000000000000000000000000000000000000'}, callback2));
batch.execute();

extend¶

web3.extend(methods)
web3.eth.extend(methods)
web3.shh.extend(methods)
web3.bzz.extend(methods)
...

Allows extending the web3 modules.

Note

You also have *.extend.formatters as additional formatter functions to be used for in and output formatting. Please see the source file for function details.

Parameters¶

methods - Object: Extension object with array of methods description objects as follows:
- property - String: (optional) The name of the property to add to the module. If no property is set it will be added to the module directly.
- methods - Array: The array of method descriptions:
  
  name - String: Name of the method to add.
  
  call - String: The RPC method name.
  
  params - Number: (optional) The number of parameters for that function. Default 0.
  
  inputFormatter - Array: (optional) Array of inputformatter functions. Each array item responds to a function parameter, so if you want some parameters not to be formatted, add a null instead.
  
  outputFormatter - ``Function: (optional) Can be used to format the output of the method.

Returns¶

Object: The extended module.

Example¶

web3.extend({
    property: 'myModule',
    methods: [{
        name: 'getBalance',
        call: 'eth_getBalance',
        params: 2,
        inputFormatter: [web3.extend.formatters.inputAddressFormatter, web3.extend.formatters.inputDefaultBlockNumberFormatter],
        outputFormatter: web3.utils.hexToNumberString
    },{
        name: 'getGasPriceSuperFunction',
        call: 'eth_gasPriceSuper',
        params: 2,
        inputFormatter: [null, web3.utils.numberToHex]
    }]
});

web3.extend({
    methods: [{
        name: 'directCall',
        call: 'eth_callForFun',
    }]
});

console.log(web3);
> Web3 {
    myModule: {
        getBalance: function(){},
        getGasPriceSuperFunction: function(){}
    },
    directCall: function(){},
    eth: Eth {...},
    bzz: Bzz {...},
    ...
}

newAccount¶

web3.eth.personal.newAccount(password, [callback])

Creates a new account.

Note

Never call this function over a unsecured Websocket or HTTP provider, as your password will be send in plain text!

Parameters¶

password - String: The password to encrypt this account with.

Returns¶

Promise returns String: The address of the newly created account.

Example¶

web3.eth.personal.newAccount('!@superpassword')
.then(console.log);
> '0x1234567891011121314151617181920212223456'

sign¶

web3.eth.personal.sign(dataToSign, address, password [, callback])

The sign method calculates an Ethereum specific signature with:

sign(keccak256("\x19Ethereum Signed Message:\n" + dataToSign.length + dataToSign)))

Adding a prefix to the message makes the calculated signature recognisable as an Ethereum specific signature.

If you have the original message and the signed message, you can discover the signing account address using web3.eth.personal.ecRecover (See example below)

Note

Sending your account password over an unsecured HTTP RPC connection is highly unsecure.

Parameters¶

String - Data to sign. If String it will be converted using web3.utils.utf8ToHex.
String - Address to sign data with.
String - The password of the account to sign data with.
Function - (optional) Optional callback, returns an error object as first parameter and the result as second.

Returns¶

Promise returns String - The signature.

Example¶

web3.eth.personal.sign("Hello world", "0x11f4d0A3c12e86B4b5F39B213F7E19D048276DAe", "test password!")
.then(console.log);
> "0x30755ed65396facf86c53e6217c52b4daebe72aa4941d89635409de4c9c7f9466d4e9aaec7977f05e923889b33c0d0dd27d7226b6e6f56ce737465c5cfd04be400"

// the below is the same
web3.eth.personal.sign(web3.utils.utf8ToHex("Hello world"), "0x11f4d0A3c12e86B4b5F39B213F7E19D048276DAe", "test password!")
.then(console.log);
> "0x30755ed65396facf86c53e6217c52b4daebe72aa4941d89635409de4c9c7f9466d4e9aaec7977f05e923889b33c0d0dd27d7226b6e6f56ce737465c5cfd04be400"

// recover the signing account address using original message and signed message
web3.eth.personal.ecRecover("Hello world", "0x30755ed65396...etc...")
.then(console.log);
> "0x11f4d0A3c12e86B4b5F39B213F7E19D048276DAe"

ecRecover¶

web3.eth.personal.ecRecover(dataThatWasSigned, signature [, callback])

Recovers the account that signed the data.

Parameters¶

String - Data that was signed. If String it will be converted using web3.utils.utf8ToHex.
String - The signature.
Function - (optional) Optional callback, returns an error object as first parameter and the result as second.

Returns¶

Promise returns String - The account.

Example¶

web3.eth.personal.ecRecover("Hello world", "0x30755ed65396facf86c53e6217c52b4daebe72aa4941d89635409de4c9c7f9466d4e9aaec7977f05e923889b33c0d0dd27d7226b6e6f56ce737465c5cfd04be400").then(console.log);
> "0x11f4d0A3c12e86B4b5F39B213F7E19D048276DAe"

signTransaction¶

web3.eth.personal.signTransaction(transaction, password [, callback])

Signs a transaction. This account needs to be unlocked.

Note

Sending your account password over an unsecured HTTP RPC connection is highly unsecure.

Parameters¶

Object - The transaction data to sign web3.eth.sendTransaction() for more.
String - The password of the from account, to sign the transaction with.
Function - (optional) Optional callback, returns an error object as first parameter and the result as second.

Returns¶

Promise returns Object - The RLP encoded transaction. The raw property can be used to send the transaction using web3.eth.sendSignedTransaction.

Example¶

web3.eth.signTransaction({
    from: "0xEB014f8c8B418Db6b45774c326A0E64C78914dC0",
    gasPrice: "20000000000",
    gas: "21000",
    to: '0x3535353535353535353535353535353535353535',
    value: "1000000000000000000",
    data: ""
}, 'MyPassword!').then(console.log);
> {
    raw: '0xf86c808504a817c800825208943535353535353535353535353535353535353535880de0b6b3a76400008025a04f4c17305743700648bc4f6cd3038ec6f6af0df73e31757007b7f59df7bee88da07e1941b264348e80c78c4027afc65a87b0a5e43e86742b8ca0823584c6788fd0',
    tx: {
        nonce: '0x0',
        gasPrice: '0x4a817c800',
        gas: '0x5208',
        to: '0x3535353535353535353535353535353535353535',
        value: '0xde0b6b3a7640000',
        input: '0x',
        v: '0x25',
        r: '0x4f4c17305743700648bc4f6cd3038ec6f6af0df73e31757007b7f59df7bee88d',
        s: '0x7e1941b264348e80c78c4027afc65a87b0a5e43e86742b8ca0823584c6788fd0',
        hash: '0xda3be87732110de6c1354c83770aae630ede9ac308d9f7b399ecfba23d923384'
    }
}

sendTransaction¶

web3.eth.personal.sendTransaction(transactionOptions, password [, callback])

This method sends a transaction over the management API.

Note

Sending your account password over an unsecured HTTP RPC connection is highly unsecure.

Parameters¶

Object - The transaction options
String - The passphrase for the current account
Function - (optional) Optional callback, returns an error object as first parameter and the result as second.

Returns¶

Promise<string> - The transaction hash.

Example¶

web3.eth.sendTransaction({
    from: "0xEB014f8c8B418Db6b45774c326A0E64C78914dC0",
    gasPrice: "20000000000",
    gas: "21000",
    to: '0x3535353535353535353535353535353535353535',
    value: "1000000000000000000",
    data: ""
}, 'MyPassword!').then(console.log);
> '0xda3be87732110de6c1354c83770aae630ede9ac308d9f7b399ecfba23d923384'

unlockAccount¶

web3.eth.personal.unlockAccount(address, password, unlockDuraction [, callback])

Signs data using a specific account.

Note

Sending your account password over an unsecured HTTP RPC connection is highly unsecure.

Parameters¶

address - String: The account address.
password - String - The password of the account.
unlockDuration - Number - The duration for the account to remain unlocked.

Example¶

web3.eth.personal.unlockAccount("0x11f4d0A3c12e86B4b5F39B213F7E19D048276DAe", "test password!", 600)
.then(console.log('Account unlocked!'));
> "Account unlocked!"

lockAccount¶

web3.eth.personal.lockAccount(address [, callback])

Locks the given account.

Note

Sending your account password over an unsecured HTTP RPC connection is highly unsecure.

Parameters¶

1. address - String: The account address. 4. Function - (optional) Optional callback, returns an error object as first parameter and the result as second.

Returns¶

Promise<boolean>

Example¶

web3.eth.personal.lockAccount("0x11f4d0A3c12e86B4b5F39B213F7E19D048276DAe")
.then(console.log('Account locked!'));
> "Account locked!"

getAccounts¶

web3.eth.personal.getAccounts([callback])

Returns a list of accounts the node controls by using the provider and calling the RPC method personal_listAccounts. Using web3.eth.accounts.create() will not add accounts into this list. For that use web3.eth.personal.newAccount().

The results are the same as web3.eth.getAccounts() except that calls the RPC method eth_accounts.

Returns¶

Promise<Array> - An array of addresses controlled by node.

Example¶

web3.eth.personal.getAccounts()
.then(console.log);
> ["0x11f4d0A3c12e86B4b5F39B213F7E19D048276DAe", "0xDCc6960376d6C6dEa93647383FfB245CfCed97Cf"]

importRawKey¶

web3.eth.personal.importRawKey(privateKey, password)

Imports the given private key into the key store, encrypting it with the passphrase.

Returns the address of the new account.

Note

Sending your account password over an unsecured HTTP RPC connection is highly unsecure.

Parameters¶

privateKey - String - An unencrypted private key (hex string).
password - String - The password of the account.

Returns¶

Promise<string> - The address of the account.

Example¶

web3.eth.personal.importRawKey("cd3376bb711cb332ee3fb2ca04c6a8b9f70c316fcdf7a1f44ef4c7999483295e", "password1234")
.then(console.log);
> "0x8f337bf484b2fc75e4b0436645dcc226ee2ac531"

web3.eth.ens¶

The web3.eth.ens functions let you interacting with ENS.

registry¶

web3.eth.ens.registry;

Returns the network specific ENS registry.

Returns¶

Registry - The current ENS registry.

Example¶

web3.eth.ens.registry;
> {
    ens: ENS,
    contract: Contract,
    owner: Function(name),
    resolve: Function(name)
}

resolver¶

web3.eth.ens.resolver(name);

Returns the resolver contract to an Ethereum address.

Returns¶

Reslver - The ENS resolver for this name.

Example¶

web3.eth.ens.resolver('ethereum.eth').then(function (contract) {
    console.log(contract);
});
> Contract<Resolver>

getAddress¶

web3.eth.ens.getAddress(ENSName);

Resolves an ENS name to an Ethereum address.

Parameters¶

ENSName - String: The ENS name to resolve.

Returns¶

String - The Ethereum address of the given name.

Example¶

web3.eth.ens.getAddress('ethereum.eth').then(function (address) {
    console.log(address);
})
> 0xfB6916095ca1df60bB79Ce92cE3Ea74c37c5d359

setAddress¶

web3.eth.ens.setAddress(ENSName, address, options);

Sets the address of an ENS name in his resolver.

Parameters¶

ENSName - String: The ENS name.
address - String: The address to set.
options - Object: The options used for sending.
- from - String: The address the transaction should be sent from.
- gasPrice - String (optional): The gas price in wei to use for this transaction.
- gas - Number (optional): The maximum gas provided for this transaction (gas limit).

Emits an AddrChanged event.

Example¶

web3.eth.ens.setAddress(
    'ethereum.eth',
    '0xfB6916095ca1df60bB79Ce92cE3Ea74c37c5d359',
    {
        from: '0x9CC9a2c777605Af16872E0997b3Aeb91d96D5D8c'
    }
).then(function (result) {
         console.log(result.events);
});
> AddrChanged(...)

// Or using the event emitter

web3.eth.ens.setAddress(
    'ethereum.eth',
    '0xfB6916095ca1df60bB79Ce92cE3Ea74c37c5d359',
    {
        from: '0x9CC9a2c777605Af16872E0997b3Aeb91d96D5D8c'
    }
)
.on('transactionHash', function(hash){
    ...
})
.on('confirmation', function(confirmationNumber, receipt){
    ...
})
.on('receipt', function(receipt){
    ...
})
.on('error', console.error);

// Or listen to the AddrChanged event on the resolver

web3.eth.ens.resolver('ethereum.eth').then(function (resolver) {
    resolver.events.AddrChanged({fromBlock: 0}, function(error, event) {
        console.log(event);
    })
    .on('data', function(event){
        console.log(event);
    })
    .on('changed', function(event){
        // remove event from local database
    })
    .on('error', console.error);
});


For further information on the handling of contract events please see here contract-events_.

getPubkey¶

web3.eth.ens.getPubkey(ENSName);

Returns the X and Y coordinates of the curve point for the public key.

Parameters¶

ENSName - String: The ENS name.

Returns¶

Object<String, String> - The X and Y coordinates.

Example¶

web3.eth.ens.getPubkey('ethereum.eth').then(function (result) {
    console.log(result)
});
> {
    "0": "0x0000000000000000000000000000000000000000000000000000000000000000",
    "1": "0x0000000000000000000000000000000000000000000000000000000000000000",
    "x": "0x0000000000000000000000000000000000000000000000000000000000000000",
    "y": "0x0000000000000000000000000000000000000000000000000000000000000000"
}

setPubkey¶

web3.eth.ens.setPubkey(ENSName, x, y, options);

Sets the SECP256k1 public key associated with an ENS node

Parameters¶

ENSName - String: The ENS name.
x - String: The X coordinate of the public key.
y - String: The Y coordinate of the public key.
options - Object: The options used for sending.
- from - String: The address the transaction should be sent from.
- gasPrice - String (optional): The gas price in wei to use for this transaction.
- gas - Number (optional): The maximum gas provided for this transaction (gas limit).

Emits an PubkeyChanged event.

Example¶

web3.eth.ens.setPubkey(
    'ethereum.eth',
    '0x0000000000000000000000000000000000000000000000000000000000000000',
    '0x0000000000000000000000000000000000000000000000000000000000000000',
    {
        from: '0x9CC9a2c777605Af16872E0997b3Aeb91d96D5D8c'
    }
).then(function (result) {
    console.log(result.events);
});
> PubkeyChanged(...)

// Or using the event emitter

web3.eth.ens.setPubkey(
    'ethereum.eth',
    '0x0000000000000000000000000000000000000000000000000000000000000000',
    '0x0000000000000000000000000000000000000000000000000000000000000000',
    {
        from: '0x9CC9a2c777605Af16872E0997b3Aeb91d96D5D8c'
    }
)
.on('transactionHash', function(hash){
    ...
})
.on('confirmation', function(confirmationNumber, receipt){
    ...
})
.on('receipt', function(receipt){
    ...
})
.on('error', console.error);

// Or listen to the PubkeyChanged event on the resolver

web3.eth.ens.resolver('ethereum.eth').then(function (resolver) {
    resolver.events.PubkeyChanged({fromBlock: 0}, function(error, event) {
        console.log(event);
    })
    .on('data', function(event){
        console.log(event);
    })
    .on('changed', function(event){
        // remove event from local database
    })
    .on('error', console.error);
});


For further information on the handling of contract events please see here contract-events_.

getContent¶

web3.eth.ens.getContent(ENSName);

Returns the content hash associated with an ENS node.

Parameters¶

ENSName - String: The ENS name.

Returns¶

String - The content hash associated with an ENS node.

Example¶

web3.eth.ens.getContent('ethereum.eth').then(function (result) {
    console.log(result);
});
> "0x0000000000000000000000000000000000000000000000000000000000000000"

setContent¶

web3.eth.ens.setContent(ENSName, hash, options);

Sets the content hash associated with an ENS node.

Parameters¶

ENSName - String: The ENS name.
hash - String: The content hash to set.
options - Object: The options used for sending.
- from - String: The address the transaction should be sent from.
- gasPrice - String (optional): The gas price in wei to use for this transaction.
- gas - Number (optional): The maximum gas provided for this transaction (gas limit).

Emits an ContentChanged event.

Example¶

web3.eth.ens.setContent(
    'ethereum.eth',
    '0x0000000000000000000000000000000000000000000000000000000000000000',
    {
        from: '0x9CC9a2c777605Af16872E0997b3Aeb91d96D5D8c'
    }
).then(function (result) {
         console.log(result.events);
 });
> ContentChanged(...)

// Or using the event emitter

web3.eth.ens.setContent(
    'ethereum.eth',
    '0x0000000000000000000000000000000000000000000000000000000000000000',
    {
        from: '0x9CC9a2c777605Af16872E0997b3Aeb91d96D5D8c'
    }
)
.on('transactionHash', function(hash){
    ...
})
.on('confirmation', function(confirmationNumber, receipt){
    ...
})
.on('receipt', function(receipt){
    ...
})
.on('error', console.error);

// Or listen to the ContentChanged event on the resolver

web3.eth.ens.resolver('ethereum.eth').then(function (resolver) {
    resolver.events.ContentChanged({fromBlock: 0}, function(error, event) {
        console.log(event);
    })
    .on('data', function(event){
        console.log(event);
    })
    .on('changed', function(event){
        // remove event from local database
    })
    .on('error', console.error);
});


For further information on the handling of contract events please see here contract-events_.

getMultihash¶

web3.eth.ens.getMultihash(ENSName);

Returns the multihash associated with an ENS node.

Parameters¶

ENSName - String: The ENS name.

Returns¶

String - The associated multihash.

Example¶

web3.eth.ens.getMultihash('ethereum.eth').then(function (result) {
    console.log(result);
});
> 'QmXpSwxdmgWaYrgMUzuDWCnjsZo5RxphE3oW7VhTMSCoKK'

setMultihash¶

web3.eth.ens.setMultihash(ENSName, hash, options);

Sets the multihash associated with an ENS node.

Parameters¶

ENSName - String: The ENS name.
hash - String: The multihash to set.
options - Object: The options used for sending.
- from - String: The address the transaction should be sent from.
- gasPrice - String (optional): The gas price in wei to use for this transaction.
- gas - Number (optional): The maximum gas provided for this transaction (gas limit).

Emits an ``MultihashChanged``event.

Example¶

web3.eth.ens.setMultihash(
    'ethereum.eth',
    'QmXpSwxdmgWaYrgMUzuDWCnjsZo5RxphE3oW7VhTMSCoKK',
    {
        from: '0x9CC9a2c777605Af16872E0997b3Aeb91d96D5D8c'
    }
).then(function (result) {
    console.log(result.events);
});
> MultihashChanged(...)

// Or using the event emitter

web3.eth.ens.setMultihash(
    'ethereum.eth',
    'QmXpSwxdmgWaYrgMUzuDWCnjsZo5RxphE3oW7VhTMSCoKK',
    {
        from: '0x9CC9a2c777605Af16872E0997b3Aeb91d96D5D8c'
    }
)
.on('transactionHash', function(hash){
    ...
})
.on('confirmation', function(confirmationNumber, receipt){
    ...
})
.on('receipt', function(receipt){
    ...
})
.on('error', console.error);


For further information on the handling of contract events please see here contract-events_.

ENS events¶

The ENS API provides the possibility for listening to all ENS related events.

Known resolver events¶

AddrChanged(node bytes32, a address)

2. ContentChanged(node bytes32, hash bytes32) 4. NameChanged(node bytes32, name string) 5. ABIChanged(node bytes32, contentType uint256) 6. PubkeyChanged(node bytes32, x bytes32, y bytes32)

Example¶

web3.eth.ens.resolver('ethereum.eth').then(function (resolver) {
    resolver.events.AddrChanged({fromBlock: 0}, function(error, event) {
        console.log(event);
    })
    .on('data', function(event){
        console.log(event);
    })
    .on('changed', function(event){
        // remove event from local database
    })
    .on('error', console.error);
});
> {
    returnValues: {
        node: '0x123456789...',
        a: '0x123456789...',
    },
    raw: {
        data: '0x7f9fade1c0d57a7af66ab4ead79fade1c0d57a7af66ab4ead7c2c2eb7b11a91385',
        topics: [
            '0xfd43ade1c09fade1c0d57a7af66ab4ead7c2c2eb7b11a91ffdd57a7af66ab4ead7',
            '0x7f9fade1c0d57a7af66ab4ead79fade1c0d57a7af66ab4ead7c2c2eb7b11a91385'
        ]
    },
    event: 'AddrChanged',
    signature: '0xfd43ade1c09fade1c0d57a7af66ab4ead7c2c2eb7b11a91ffdd57a7af66ab4ead7',
    logIndex: 0,
    transactionIndex: 0,
    transactionHash: '0x7f9fade1c0d57a7af66ab4ead79fade1c0d57a7af66ab4ead7c2c2eb7b11a91385',
    blockHash: '0xfd43ade1c09fade1c0d57a7af66ab4ead7c2c2eb7b11a91ffdd57a7af66ab4ead7',
    blockNumber: 1234,
    address: '0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe'
}

Known registry events¶

Transfer(node bytes32, owner address)

2. NewOwner(node bytes32, label bytes32, owner address) 4. NewResolver(node bytes32, resolver address) 5. NewTTL(node bytes32, ttl uint64)

Example¶

web3.eth.ens.resistry.then(function (registry) {
    registry.events.Transfer({fromBlock: 0}, , function(error, event) {
          console.log(event);
      })
      .on('data', function(event){
          console.log(event);
      })
      .on('changed', function(event){
          // remove event from local database
      })
      .on('error', console.error);
});
> {
    returnValues: {
        node: '0x123456789...',
        owner: '0x123456789...',
    },
    raw: {
        data: '0x7f9fade1c0d57a7af66ab4ead79fade1c0d57a7af66ab4ead7c2c2eb7b11a91385',
        topics: [
            '0xfd43ade1c09fade1c0d57a7af66ab4ead7c2c2eb7b11a91ffdd57a7af66ab4ead7',
            '0x7f9fade1c0d57a7af66ab4ead79fade1c0d57a7af66ab4ead7c2c2eb7b11a91385'
        ]
    },
    event: 'Transfer',
    signature: '0xfd43ade1c09fade1c0d57a7af66ab4ead7c2c2eb7b11a91ffdd57a7af66ab4ead7',
    logIndex: 0,
    transactionIndex: 0,
    transactionHash: '0x7f9fade1c0d57a7af66ab4ead79fade1c0d57a7af66ab4ead7c2c2eb7b11a91385',
    blockHash: '0xfd43ade1c09fade1c0d57a7af66ab4ead7c2c2eb7b11a91ffdd57a7af66ab4ead7',
    blockNumber: 1234,
    address: '0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe'
}

For further information on the handling of contract events please see here contract-events_.

web3.eth.Iban¶

The web3.eth.Iban function lets convert Ethereum addresses from and to IBAN and BBAN.

Iban instance¶

This’s instance of Iban

> Iban { _iban: 'XE7338O073KYGTWWZN0F2WZ0R8PX5ZPPZS' }

Iban contructor¶

new web3.eth.Iban(ibanAddress)

Generates a iban object with conversion methods and validity checks. Also has singleton functions for conversion like Iban.toAddress(), Iban.toIban(), Iban.fromAddress(), Iban.fromBban(), Iban.createIndirect(), Iban.isValid().

Parameters¶

String: the IBAN address to instantiate an Iban instance from.

Returns¶

Object - The Iban instance.

Example¶

var iban = new web3.eth.Iban("XE7338O073KYGTWWZN0F2WZ0R8PX5ZPPZS");
> Iban { _iban: 'XE7338O073KYGTWWZN0F2WZ0R8PX5ZPPZS' }

toAddress¶

static function

web3.eth.Iban.toAddress(ibanAddress)

Singleton: Converts a direct IBAN address into an Ethereum address.

Note

This method also exists on the IBAN instance.

Parameters¶

String: the IBAN address to convert.

Returns¶

String - The Ethereum address.

Example¶

web3.eth.Iban.toAddress("XE7338O073KYGTWWZN0F2WZ0R8PX5ZPPZS");
> "0x00c5496aEe77C1bA1f0854206A26DdA82a81D6D8"

toIban¶

static function

web3.eth.Iban.toIban(address)

Singleton: Converts an Ethereum address to a direct IBAN address.

Parameters¶

String: the Ethereum address to convert.

Returns¶

String - The IBAN address.

Example¶

web3.eth.Iban.toIban("0x00c5496aEe77C1bA1f0854206A26DdA82a81D6D8");
> "XE7338O073KYGTWWZN0F2WZ0R8PX5ZPPZS"

static function, return IBAN instance

fromAddress¶

web3.eth.Iban.fromAddress(address)

Singleton: Converts an Ethereum address to a direct IBAN instance.

Parameters¶

String: the Ethereum address to convert.

Returns¶

Object - The IBAN instance.

Example¶

web3.eth.Iban.fromAddress("0x00c5496aEe77C1bA1f0854206A26DdA82a81D6D8");
> Iban {_iban: "XE7338O073KYGTWWZN0F2WZ0R8PX5ZPPZS"}

static function, return IBAN instance

fromBban¶

web3.eth.Iban.fromBban(bbanAddress)

Singleton: Converts an BBAN address to a direct IBAN instance.

Parameters¶

String: the BBAN address to convert.

Returns¶

Object - The IBAN instance.

Example¶

web3.eth.Iban.fromBban('ETHXREGGAVOFYORK');
> Iban {_iban: "XE7338O073KYGTWWZN0F2WZ0R8PX5ZPPZS"}

static function, return IBAN instance

createIndirect¶

web3.eth.Iban.createIndirect(options)

Singleton: Creates an indirect IBAN address from a institution and identifier.

Parameters¶

Object: the options object as follows:
- institution - String: the institution to be assigned
- identifier - String: the identifier to be assigned

Returns¶

Object - The IBAN instance.

Example¶

web3.eth.Iban.createIndirect({
    institution: "XREG",
    identifier: "GAVOFYORK"
});
> Iban {_iban: "XE7338O073KYGTWWZN0F2WZ0R8PX5ZPPZS"}

static function, return boolean

isValid¶

web3.eth.Iban.isValid(ibanAddress)

Singleton: Checks if an IBAN address is valid.

Note

This method also exists on the IBAN instance.

Parameters¶

String: the IBAN address to check.

Returns¶

Boolean

Example¶

web3.eth.Iban.isValid("XE81ETHXREGGAVOFYORK");
> true

web3.eth.Iban.isValid("XE82ETHXREGGAVOFYORK");
> false // because the checksum is incorrect

prototype.isValid¶

method of Iban instance

web3.eth.Iban.prototype.isValid()

Singleton: Checks if an IBAN address is valid.

Note

This method also exists on the IBAN instance.

Parameters¶

String: the IBAN address to check.

Returns¶

Boolean

Example¶

var iban = new web3.eth.Iban("XE81ETHXREGGAVOFYORK");
iban.isValid();
> true

prototype.isDirect¶

method of Iban instance

web3.eth.Iban.prototype.isDirect()

Checks if the IBAN instance is direct.

Parameters¶

none

Returns¶

Boolean

Example¶

var iban = new web3.eth.Iban("XE81ETHXREGGAVOFYORK");
iban.isDirect();
> false

prototype.isIndirect¶

method of Iban instance

web3.eth.Iban.prototype.isIndirect()

Checks if the IBAN instance is indirect.

Parameters¶

none

Returns¶

Boolean

Example¶

var iban = new web3.eth.Iban("XE81ETHXREGGAVOFYORK");
iban.isIndirect();
> true

prototype.checksum¶

method of Iban instance

web3.eth.Iban.prototype.checksum()

Returns the checksum of the IBAN instance.

Parameters¶

none

Returns¶

String: The checksum of the IBAN

Example¶

var iban = new web3.eth.Iban("XE81ETHXREGGAVOFYORK");
iban.checksum();
> "81"

prototype.institution¶

method of Iban instance

web3.eth.Iban.prototype.institution()

Returns the institution of the IBAN instance.

Parameters¶

none

Returns¶

String: The institution of the IBAN

Example¶

var iban = new web3.eth.Iban("XE81ETHXREGGAVOFYORK");
iban.institution();
> 'XREG'

prototype.client¶

method of Iban instance

web3.eth.Iban.prototype.client()

Returns the client of the IBAN instance.

Parameters¶

none

Returns¶

String: The client of the IBAN

Example¶

var iban = new web3.eth.Iban("XE81ETHXREGGAVOFYORK");
iban.client();
> 'GAVOFYORK'

prototype.toAddress¶

method of Iban instance

web3.eth.Iban.prototype.toString()

Returns the Ethereum address of the IBAN instance.

Parameters¶

none

Returns¶

String: The Ethereum address of the IBAN

Example¶

var iban = new web3.eth.Iban('XE7338O073KYGTWWZN0F2WZ0R8PX5ZPPZS');
iban.toAddress();
> '0x00c5496aEe77C1bA1f0854206A26DdA82a81D6D8'

prototype.toString¶

method of Iban instance

web3.eth.Iban.prototype.toString()

Returns the IBAN address of the IBAN instance.

Parameters¶

none

Returns¶

String: The IBAN address.

Example¶

var iban = new web3.eth.Iban('XE7338O073KYGTWWZN0F2WZ0R8PX5ZPPZS');
iban.toString();
> 'XE7338O073KYGTWWZN0F2WZ0R8PX5ZPPZS'

web3.eth.abi¶

The web3.eth.abi functions let you de- and encode parameters to ABI (Application Binary Interface) for function calls to the EVM (Ethereum Virtual Machine).

encodeFunctionSignature¶

web3.eth.abi.encodeFunctionSignature(functionName);

Encodes the function name to its ABI signature, which are the first 4 bytes of the sha3 hash of the function name including types.

Parameters¶

1. functionName - String|Object: The function name to encode. or the JSON interface object of the function. If string it has to be in the form function(type,type,...), e.g: myFunction(uint256,uint32[],bytes10,bytes)

Returns¶

String - The ABI signature of the function.

Example¶

// From a JSON interface object
web3.eth.abi.encodeFunctionSignature({
    name: 'myMethod',
    type: 'function',
    inputs: [{
        type: 'uint256',
        name: 'myNumber'
    },{
        type: 'string',
        name: 'myString'
    }]
})
> 0x24ee0097

// Or string
web3.eth.abi.encodeFunctionSignature('myMethod(uint256,string)')
> '0x24ee0097'

encodeEventSignature¶

web3.eth.abi.encodeEventSignature(eventName);

Encodes the event name to its ABI signature, which are the sha3 hash of the event name including input types.

Parameters¶

1. eventName - String|Object: The event name to encode. or the JSON interface object of the event. If string it has to be in the form event(type,type,...), e.g: myEvent(uint256,uint32[],bytes10,bytes)

Returns¶

String - The ABI signature of the event.

Example¶

web3.eth.abi.encodeEventSignature('myEvent(uint256,bytes32)')
> 0xf2eeb729e636a8cb783be044acf6b7b1e2c5863735b60d6daae84c366ee87d97

// or from a json interface object
web3.eth.abi.encodeEventSignature({
    name: 'myEvent',
    type: 'event',
    inputs: [{
        type: 'uint256',
        name: 'myNumber'
    },{
        type: 'bytes32',
        name: 'myBytes'
    }]
})
> 0xf2eeb729e636a8cb783be044acf6b7b1e2c5863735b60d6daae84c366ee87d97

encodeParameter¶

web3.eth.abi.encodeParameter(type, parameter);

Encodes a parameter based on its type to its ABI representation.

Parameters¶

type - String|Object: The type of the parameter, see the solidity documentation for a list of types.
parameter - Mixed: The actual parameter to encode.

Returns¶

String - The ABI encoded parameter.

Example¶

web3.eth.abi.encodeParameter('uint256', '2345675643');
> "0x000000000000000000000000000000000000000000000000000000008bd02b7b"

web3.eth.abi.encodeParameter('uint256', '2345675643');
> "0x000000000000000000000000000000000000000000000000000000008bd02b7b"

web3.eth.abi.encodeParameter('bytes32', '0xdf3234');
> "0xdf32340000000000000000000000000000000000000000000000000000000000"

web3.eth.abi.encodeParameter('bytes', '0xdf3234');
> "0x00000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000003df32340000000000000000000000000000000000000000000000000000000000"

web3.eth.abi.encodeParameter('bytes32[]', ['0xdf3234', '0xfdfd']);
> "00000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000002df32340000000000000000000000000000000000000000000000000000000000fdfd000000000000000000000000000000000000000000000000000000000000"

web3.eth.abi.encodeParameter(
    {
        "ParentStruct": {
            "propertyOne": 'uint256',
            "propertyTwo": 'uint256',
            "childStruct": {
                "propertyOne": 'uint256',
                "propertyTwo": 'uint256'
            }
        }
    },
    {
        "propertyOne": 42,
        "propertyTwo": 56,
        "childStruct": {
            "propertyOne": 45,
            "propertyTwo": 78
        }
    }
);
> "0x000000000000000000000000000000000000000000000000000000000000002a0000000000000000000000000000000000000000000000000000000000000038000000000000000000000000000000000000000000000000000000000000002d000000000000000000000000000000000000000000000000000000000000004e"

encodeParameters¶

web3.eth.abi.encodeParameters(typesArray, parameters);

Encodes a function parameters based on its JSON interface object.

Parameters¶

typesArray - Array<String|Object>|Object: An array with types or a JSON interface of a function. See the solidity documentation for a list of types.
parameters - Array: The parameters to encode.

Returns¶

String - The ABI encoded parameters.

Example¶

web3.eth.abi.encodeParameters(['uint256','string'], ['2345675643', 'Hello!%']);
> "0x000000000000000000000000000000000000000000000000000000008bd02b7b0000000000000000000000000000000000000000000000000000000000000040000000000000000000000000000000000000000000000000000000000000000748656c6c6f212500000000000000000000000000000000000000000000000000"

web3.eth.abi.encodeParameters(['uint8[]','bytes32'], [['34','434'], '0x324567fff']);
> "0x0

web3.eth.abi.encodeParameters(
    [
        'uint8[]',
        {
            "ParentStruct": {
                "propertyOne": 'uint256',
                "propertyTwo": 'uint256',
                "ChildStruct": {
                    "propertyOne": 'uint256',
                    "propertyTwo": 'uint256'
                }
            }
        }
    ],
    [
        ['34','434'],
        {
            "propertyOne": '42',
            "propertyTwo": '56',
            "ChildStruct": {
                "propertyOne": '45',
                "propertyTwo": '78'
            }
        }
    ]
);
> "0x00000000000000000000000000000000000000000000000000000000000000a0000000000000000000000000000000000000000000000000000000000000002a0000000000000000000000000000000000000000000000000000000000000038000000000000000000000000000000000000000000000000000000000000002d000000000000000000000000000000000000000000000000000000000000004e0000000000000000000000000000000000000000000000000000000000000002000000000000000000000000000000000000000000000000000000000000002a0000000000000000000000000000000000000000000000000000000000000018"

encodeFunctionCall¶

web3.eth.abi.encodeFunctionCall(jsonInterface, parameters);

Encodes a function call using its JSON interface object and given paramaters.

Parameters¶

jsonInterface - Object: The JSON interface object of a function.
parameters - Array: The parameters to encode.

Returns¶

String - The ABI encoded function call. Means function signature + parameters.

Example¶

web3.eth.abi.encodeFunctionCall({
    name: 'myMethod',
    type: 'function',
    inputs: [{
        type: 'uint256',
        name: 'myNumber'
    },{
        type: 'string',
        name: 'myString'
    }]
}, ['2345675643', 'Hello!%']);
> "0x24ee0097000000000000000000000000000000000000000000000000000000008bd02b7b0000000000000000000000000000000000000000000000000000000000000040000000000000000000000000000000000000000000000000000000000000000748656c6c6f212500000000000000000000000000000000000000000000000000"

decodeParameter¶

web3.eth.abi.decodeParameter(type, hexString);

Decodes an ABI encoded parameter to its JavaScript type.

Parameters¶

type - String|Object: The type of the parameter, see the solidity documentation for a list of types.
hexString - String: The ABI byte code to decode.

Returns¶

Mixed - The decoded parameter.

Example¶

web3.eth.abi.decodeParameter('uint256', '0x0000000000000000000000000000000000000000000000000000000000000010');
> "16"

web3.eth.abi.decodeParameter('string', '0x0000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000000848656c6c6f212521000000000000000000000000000000000000000000000000');
> "Hello!%!"

web3.eth.abi.decodeParameter('string', '0x0000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000000848656c6c6f212521000000000000000000000000000000000000000000000000');
> "Hello!%!"

web3.eth.abi.decodeParameter(
    {
        "ParentStruct": {
          "propertyOne": 'uint256',
          "propertyTwo": 'uint256',
          "childStruct": {
            "propertyOne": 'uint256',
            "propertyTwo": 'uint256'
          }
        }
    },

, '0x000000000000000000000000000000000000000000000000000000000000002a0000000000000000000000000000000000000000000000000000000000000038000000000000000000000000000000000000000000000000000000000000002d000000000000000000000000000000000000000000000000000000000000004e');
> {
    '0': {
        '0': '42',
        '1': '56',
        '2': {
            '0': '45',
            '1': '78',
            'propertyOne': '45',
            'propertyTwo': '78'
        },
        'childStruct': {
            '0': '45',
            '1': '78',
            'propertyOne': '45',
            'propertyTwo': '78'
        },
        'propertyOne': '42',
        'propertyTwo': '56'
    },
    'ParentStruct': {
        '0': '42',
        '1': '56',
        '2': {
            '0': '45',
            '1': '78',
            'propertyOne': '45',
            'propertyTwo': '78'
        },
        'childStruct': {
            '0': '45',
            '1': '78',
            'propertyOne': '45',
            'propertyTwo': '78'
        },
        'propertyOne': '42',
        'propertyTwo': '56'
    }
}

decodeParameters¶

web3.eth.abi.decodeParameters(typesArray, hexString);

Decodes ABI encoded parameters to its JavaScript types.

Parameters¶

typesArray - Array<String|Object>|Object: An array with types or a JSON interface outputs array. See the solidity documentation for a list of types.
hexString - String: The ABI byte code to decode.

Returns¶

Object - The result object containing the decoded parameters.

Example¶

web3.eth.abi.decodeParameters(['string', 'uint256'], '0x000000000000000000000000000000000000000000000000000000000000004000000000000000000000000000000000000000000000000000000000000000ea000000000000000000000000000000000000000000000000000000000000000848656c6c6f212521000000000000000000000000000000000000000000000000');
> Result { '0': 'Hello!%!', '1': '234' }

web3.eth.abi.decodeParameters([{
    type: 'string',
    name: 'myString'
},{
    type: 'uint256',
    name: 'myNumber'
}], '0x000000000000000000000000000000000000000000000000000000000000004000000000000000000000000000000000000000000000000000000000000000ea000000000000000000000000000000000000000000000000000000000000000848656c6c6f212521000000000000000000000000000000000000000000000000');
> Result {
    '0': 'Hello!%!',
    '1': '234',
    myString: 'Hello!%!',
    myNumber: '234'
}

web3.eth.abi.decodeParameters([
  'uint8[]',
  {
    "ParentStruct": {
      "propertyOne": 'uint256',
      "propertyTwo": 'uint256',
      "childStruct": {
        "propertyOne": 'uint256',
        "propertyTwo": 'uint256'
      }
    }
  }
], '0x00000000000000000000000000000000000000000000000000000000000000a0000000000000000000000000000000000000000000000000000000000000002a0000000000000000000000000000000000000000000000000000000000000038000000000000000000000000000000000000000000000000000000000000002d000000000000000000000000000000000000000000000000000000000000004e0000000000000000000000000000000000000000000000000000000000000002000000000000000000000000000000000000000000000000000000000000002a0000000000000000000000000000000000000000000000000000000000000018');
> Result {
    '0': ['42', '24'],
    '1': {
        '0': '42',
        '1': '56',
        '2':
            {
                '0': '45',
                '1': '78',
                'propertyOne': '45',
                'propertyTwo': '78'
            },
        'childStruct':
            {
                '0': '45',
                '1': '78',
                'propertyOne': '45',
                'propertyTwo': '78'
            },
        'propertyOne': '42',
        'propertyTwo': '56'
    }
}

decodeLog¶

web3.eth.abi.decodeLog(inputs, hexString, topics);

Decodes ABI encoded log data and indexed topic data.

Parameters¶

inputs - Object: A JSON interface inputs array. See the solidity documentation for a list of types.
hexString - String: The ABI byte code in the data field of a log.
topics - Array: An array with the index parameter topics of the log, without the topic[0] if its a non-anonymous event, otherwise with topic[0].

Returns¶

Object - The result object containing the decoded parameters.

Example¶

web3.eth.abi.decodeLog([{
    type: 'string',
    name: 'myString'
},{
    type: 'uint256',
    name: 'myNumber',
    indexed: true
},{
    type: 'uint8',
    name: 'mySmallNumber',
    indexed: true
}],
'0x0000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000000748656c6c6f252100000000000000000000000000000000000000000000000000',
['0x000000000000000000000000000000000000000000000000000000000000f310', '0x0000000000000000000000000000000000000000000000000000000000000010']);
> Result {
    '0': 'Hello%!',
    '1': '62224',
    '2': '16',
    myString: 'Hello%!',
    myNumber: '62224',
    mySmallNumber: '16'
}

web3.*.net¶

The web3-net package allows you to interact with the Ethereum nodes network properties.

var Net = require('web3-net');

// "Personal.providers.givenProvider" will be set if in an Ethereum supported browser.
var net = new Net(Net.givenProvider || 'ws://some.local-or-remote.node:8546');


// or using the web3 umbrella package

var Web3 = require('web3');
var web3 = new Web3(Web3.givenProvider || 'ws://some.local-or-remote.node:8546');

// -> web3.eth.net
// -> web3.bzz.net
// -> web3.shh.net

getId¶

web3.eth.net.getId([callback])
web3.bzz.net.getId([callback])
web3.shh.net.getId([callback])

Gets the current network ID.

Parameters¶

none

Returns¶

Promise returns Number: The network ID.

Example¶

web3.eth.net.getId()
.then(console.log);
> 1

isListening¶

web3.eth.net.isListening([callback])
web3.bzz.net.isListening([callback])
web3.shh.net.isListening([callback])

Checks if the node is listening for peers.

Parameters¶

none

Returns¶

Promise returns Boolean

Example¶

web3.eth.isListening()
.then(console.log);
> true

getPeerCount¶

web3.eth.net.getPeerCount([callback])
web3.bzz.net.getPeerCount([callback])
web3.shh.net.getPeerCount([callback])

Get the number of peers connected to.

Parameters¶

none

Returns¶

Promise returns Number

Example¶

web3.eth.getPeerCount()
.then(console.log);
> 25

web3.bzz¶

Note

This API might change over time.

The web3-bzz package allows you to interact swarm the decentralized file store. For more see the Swarm Docs.

var Bzz = require('web3-bzz');

// will autodetect if the "ethereum" object is present and will either connect to the local swarm node, or the swarm-gateways.net.
// Optional you can give your own provider URL; If no provider URL is given it will use "http://swarm-gateways.net"
var bzz = new Bzz(Bzz.givenProvider || 'http://swarm-gateways.net');


// or using the web3 umbrella package

var Web3 = require('web3');
var web3 = new Web3(Web3.givenProvider || 'ws://some.local-or-remote.node:8546');

// -> web3.bzz.currentProvider // if Web3.givenProvider was an ethereum provider it will set: "http://localhost:8500" otherwise it will set: "http://swarm-gateways.net"

// set the provider manually if necessary
web3.bzz.setProvider("http://localhost:8500");

setProvider¶

web3.bzz.setProvider(myProvider)

Will change the provider for its module.

Note

When called on the umbrella package web3 it will also set the provider for all sub modules web3.eth, web3.shh, etc EXCEPT web3.bzz which needs a separate provider at all times.

Parameters¶

Object - myProvider: a valid provider.

Returns¶

Boolean

Example¶

var Bzz = require('web3-bzz');
var bzz = new Bzz('http://localhost:8500');

// change provider
bzz.setProvider('http://swarm-gateways.net');

givenProvider¶

web3.bzz.givenProvider

When using web3.js in an Ethereum compatible browser, it will set with the current native provider by that browser. Will return the given provider by the (browser) environment, otherwise null.

Returns¶

Object: The given provider set or null;

Example¶

bzz.givenProvider;
> {
    send: function(),
    on: function(),
    bzz: "http://localhost:8500",
    shh: true,
    ...
}

bzz.setProvider(bzz.givenProvider || "http://swarm-gateways.net");

currentProvider¶

bzz.currentProvider

Will return the current provider URL, otherwise null.

Returns¶

Object: The current provider URL or null;

Example¶

bzz.currentProvider;
> "http://localhost:8500"


if(!bzz.currentProvider) {
    bzz.setProvider("http://swarm-gateways.net");
}

upload¶

web3.bzz.upload(mixed)

Uploads files folders or raw data to swarm.

Parameters¶

mixed - String|Buffer|Uint8Array|Object: The data to upload, can be a file content, file Buffer/Uint8Array, multiple files, or a directory or file (only in node.js). The following types are allowed:
- String|Buffer|Uint8Array: A file content, file Uint8Array or Buffer to upload, or:
- Object:
  
  Multiple key values for files and directories. The paths will be kept the same:
  
  key must be the files path, or name, e.g. "/foo.txt" and its value is an object with:
  
  type: The mime-type of the file, e.g. "text/html".
  
  data: A file content, file Uint8Array or Buffer to upload.
  
  Upload a file or a directory from disk in Node.js. Requires and object with the following properties:
  
  path: The path to the file or directory.
  
  kind: The type of the source "directory", "file" or "data".
  
  defaultFile (optional): Path of the “defaultFile” when "kind": "directory", e.g. "/index.html".
  
  Upload file or folder in the browser. Requres and object with the following properties:
  
  pick: The file picker to launch. Can be "file", "directory" or "data".

Returns¶

Promise returning String: Returns the content hash of the manifest.

Example¶

var bzz = web3.bzz;

// raw data
bzz.upload("test file").then(function(hash) {
    console.log("Uploaded file. Address:", hash);
})

// raw directory
var dir = {
    "/foo.txt": {type: "text/plain", data: "sample file"},
    "/bar.txt": {type: "text/plain", data: "another file"}
};
bzz.upload(dir).then(function(hash) {
    console.log("Uploaded directory. Address:", hash);
});

// upload from disk in node.js
bzz.upload({
    path: "/path/to/thing",      // path to data / file / directory
    kind: "directory",           // could also be "file" or "data"
    defaultFile: "/index.html"   // optional, and only for kind === "directory"
})
.then(console.log)
.catch(console.log);

// upload from disk in the browser
bzz.upload({pick: "file"}) // could also be "directory" or "data"
.then(console.log);

download¶

web3.bzz.download(bzzHash [, localpath])

Downloads files and folders from swarm, as buffer or to disk (only node.js).

Parameters¶

bzzHash - String: The file or directory to download. If the hash is a raw file it will return a Buffer, if a manifest file, it will return the directory structure. If the localpath is given, it will return that path where it downloaded the files to.
localpath - String: The local folder to download the content into. (only node.js)

Returns¶

Promise returning Buffer|Object|String: The Buffer of the file downloaded, an object with the directory structure, or the path where it was downloaded to.

Example¶

var bzz = web3.bzz;

// download raw file
var fileHash = "a5c10851ef054c268a2438f10a21f6efe3dc3dcdcc2ea0e6a1a7a38bf8c91e23";
bzz.download(fileHash).then(function(buffer) {
    console.log("Downloaded file:", buffer.toString());
});

// download directory, if the hash is manifest file.
var dirHash = "7e980476df218c05ecfcb0a2ca73597193a34c5a9d6da84d54e295ecd8e0c641";
bzz.download(dirHash).then(function(dir) {
    console.log("Downloaded directory:");
    > {
        'bar.txt': { type: 'text/plain', data: <Buffer 61 6e 6f 74 68 65 72 20 66 69 6c 65> },
        'foo.txt': { type: 'text/plain', data: <Buffer 73 61 6d 70 6c 65 20 66 69 6c 65> }
    }
});

// download file/directory to disk (only node.js)
var dirHash = "a5c10851ef054c268a2438f10a21f6efe3dc3dcdcc2ea0e6a1a7a38bf8c91e23";
bzz.download(dirHash, "/target/dir")
.then(path => console.log(`Downloaded directory to ${path}.`))
.catch(console.log);

pick¶

web3.bzz.pick.file()
web3.bzz.pick.directory()
web3.bzz.pick.data()

Opens a file picker in the browser to select file(s), directory or data.

Parameters¶

none

Returns¶

Promise returning Object: Returns the file or multiple files.

Example¶

web3.bzz.pick.file()
.then(console.log);
> {
    ...
}

web3.shh¶

The web3-shh package allows you to interact with the whisper protocol for broadcasting. For more see Whisper Overview.

var Shh = require('web3-shh');

// "Shh.providers.givenProvider" will be set if in an Ethereum supported browser.
var shh = new Shh(Shh.givenProvider || 'ws://some.local-or-remote.node:8546');

// or using the web3 umbrella package

var Web3 = require('web3');
var web3 = new Web3(Web3.givenProvider || 'ws://some.local-or-remote.node:8546');

// -> web3.shh

setProvider¶

web3.setProvider(myProvider)
web3.eth.setProvider(myProvider)
web3.shh.setProvider(myProvider)
web3.bzz.setProvider(myProvider)
...

Will change the provider for its module.

Note

When called on the umbrella package web3 it will also set the provider for all sub modules web3.eth, web3.shh, etc EXCEPT web3.bzz which needs a separate provider at all times.

Parameters¶

Object - myProvider: a valid provider.

Returns¶

Boolean

Example¶

var Web3 = require('web3');
var web3 = new Web3('http://localhost:8545');
// or
var web3 = new Web3(new Web3.providers.HttpProvider('http://localhost:8545'));

// change provider
web3.setProvider('ws://localhost:8546');
// or
web3.setProvider(new Web3.providers.WebsocketProvider('ws://localhost:8546'));

// Using the IPC provider in node.js
var net = require('net');
var web3 = new Web3('/Users/myuser/Library/Ethereum/geth.ipc', net); // mac os path
// or
var web3 = new Web3(new Web3.providers.IpcProvider('/Users/myuser/Library/Ethereum/geth.ipc', net)); // mac os path
// on windows the path is: "\\\\.\\pipe\\geth.ipc"
// on linux the path is: "/users/myuser/.ethereum/geth.ipc"

providers¶

web3.providers
web3.eth.providers
web3.shh.providers
web3.bzz.providers
...

Contains the current available providers.

Value¶

Object with the following providers:

Object - HttpProvider: The HTTP provider is deprecated, as it won’t work for subscriptions.

Object - WebsocketProvider: The Websocket provider is the standard for usage in legacy browsers.

Object - IpcProvider: The IPC provider is used node.js dapps when running a local node. Gives the most secure connection.

Example¶

var Web3 = require('web3');
// use the given Provider, e.g in Mist, or instantiate a new websocket provider
var web3 = new Web3(Web3.givenProvider || 'ws://remotenode.com:8546');
// or
var web3 = new Web3(Web3.givenProvider || new Web3.providers.WebsocketProvider('ws://remotenode.com:8546'));

// Using the IPC provider in node.js
var net = require('net');

var web3 = new Web3('/Users/myuser/Library/Ethereum/geth.ipc', net); // mac os path
// or
var web3 = new Web3(new Web3.providers.IpcProvider('/Users/myuser/Library/Ethereum/geth.ipc', net)); // mac os path
// on windows the path is: "\\\\.\\pipe\\geth.ipc"
// on linux the path is: "/users/myuser/.ethereum/geth.ipc"

givenProvider¶

web3.givenProvider
web3.eth.givenProvider
web3.shh.givenProvider
web3.bzz.givenProvider
...

When using web3.js in an Ethereum compatible browser, it will set with the current native provider by that browser. Will return the given provider by the (browser) environment, otherwise null.

Returns¶

Object: The given provider set or null;

Example¶

currentProvider¶

web3.currentProvider
web3.eth.currentProvider
web3.shh.currentProvider
web3.bzz.currentProvider
...

Will return the current provider, otherwise null.

Returns¶

Object: The current provider set or null;

Example¶

BatchRequest¶

new web3.BatchRequest()
new web3.eth.BatchRequest()
new web3.shh.BatchRequest()
new web3.bzz.BatchRequest()

Class to create and execute batch requests.

Parameters¶

none

Returns¶

Object: With the following methods:

add(request): To add a request object to the batch call.

execute(): Will execute the batch request.

Example¶

var contract = new web3.eth.Contract(abi, address);

var batch = new web3.BatchRequest();
batch.add(web3.eth.getBalance.request('0x0000000000000000000000000000000000000000', 'latest', callback));
batch.add(contract.methods.balance(address).call.request({from: '0x0000000000000000000000000000000000000000'}, callback2));
batch.execute();

extend¶

web3.extend(methods)
web3.eth.extend(methods)
web3.shh.extend(methods)
web3.bzz.extend(methods)
...

Allows extending the web3 modules.

Note

You also have *.extend.formatters as additional formatter functions to be used for in and output formatting. Please see the source file for function details.

Parameters¶

methods - Object: Extension object with array of methods description objects as follows:
- property - String: (optional) The name of the property to add to the module. If no property is set it will be added to the module directly.
- methods - Array: The array of method descriptions:
  
  name - String: Name of the method to add.
  
  call - String: The RPC method name.
  
  params - Number: (optional) The number of parameters for that function. Default 0.
  
  inputFormatter - Array: (optional) Array of inputformatter functions. Each array item responds to a function parameter, so if you want some parameters not to be formatted, add a null instead.
  
  outputFormatter - ``Function: (optional) Can be used to format the output of the method.

Returns¶

Object: The extended module.

Example¶

web3.extend({
    property: 'myModule',
    methods: [{
        name: 'getBalance',
        call: 'eth_getBalance',
        params: 2,
        inputFormatter: [web3.extend.formatters.inputAddressFormatter, web3.extend.formatters.inputDefaultBlockNumberFormatter],
        outputFormatter: web3.utils.hexToNumberString
    },{
        name: 'getGasPriceSuperFunction',
        call: 'eth_gasPriceSuper',
        params: 2,
        inputFormatter: [null, web3.utils.numberToHex]
    }]
});

web3.extend({
    methods: [{
        name: 'directCall',
        call: 'eth_callForFun',
    }]
});

console.log(web3);
> Web3 {
    myModule: {
        getBalance: function(){},
        getGasPriceSuperFunction: function(){}
    },
    directCall: function(){},
    eth: Eth {...},
    bzz: Bzz {...},
    ...
}

getId¶

web3.eth.net.getId([callback])
web3.bzz.net.getId([callback])
web3.shh.net.getId([callback])

Gets the current network ID.

Parameters¶

none

Returns¶

Promise returns Number: The network ID.

Example¶

web3.eth.net.getId()
.then(console.log);
> 1

isListening¶

web3.eth.net.isListening([callback])
web3.bzz.net.isListening([callback])
web3.shh.net.isListening([callback])

Checks if the node is listening for peers.

Parameters¶

none

Returns¶

Promise returns Boolean

Example¶

web3.eth.isListening()
.then(console.log);
> true

getPeerCount¶

web3.eth.net.getPeerCount([callback])
web3.bzz.net.getPeerCount([callback])
web3.shh.net.getPeerCount([callback])

Get the number of peers connected to.

Parameters¶

none

Returns¶

Promise returns Number

Example¶

web3.eth.getPeerCount()
.then(console.log);
> 25

getVersion¶

web3.shh.getVersion([callback])

Returns the version of the running whisper.

Parameters¶

Function - (optional) Optional callback, returns an error object as first parameter and the result as second.

Returns¶

String - The version of the current whisper running.

Example¶

web3.shh.getVersion()
.then(console.log);
> "5.0"

getInfo¶

web3.shh.getInfo([callback])

Gets information about the current whisper node.

Parameters¶

Function - (optional) Optional callback, returns an error object as first parameter and the result as second.

Returns¶

Object - The information of the node with the following properties:

messages - Number: Number of currently floating messages.

maxMessageSize - Number: The current message size limit in bytes.

memory - Number: The memory size of the floating messages in bytes.

minPow - Number: The current minimum PoW requirement.

Example¶

web3.shh.getInfo()
.then(console.log);
> {
    "minPow": 0.8,
    "maxMessageSize": 12345,
    "memory": 1234335,
    "messages": 20
}

setMaxMessageSize¶

web3.shh.setMaxMessageSize(size, [callback])

Sets the maximal message size allowed by this node. Incoming and outgoing messages with a larger size will be rejected. Whisper message size can never exceed the limit imposed by the underlying P2P protocol (10 Mb).

Parameters¶

Number - Message size in bytes.
Function - (optional) Optional callback, returns an error object as first parameter and the result as second.

Returns¶

Boolean - true on success, error on failure.

Example¶

web3.shh.setMaxMessageSize(1234565)
.then(console.log);
> true

setMinPoW¶

web3.shh.setMinPoW(pow, [callback])

Sets the minimal PoW required by this node.

This experimental function was introduced for the future dynamic adjustment of PoW requirement. If the node is overwhelmed with messages, it should raise the PoW requirement and notify the peers. The new value should be set relative to the old value (e.g. double). The old value can be obtained via web3.shh.getInfo().

Parameters¶

Number - The new PoW requirement.
Function - (optional) Optional callback, returns an error object as first parameter and the result as second.

Returns¶

Boolean - true on success, error on failure.

Example¶

web3.shh.setMinPoW(0.9)
.then(console.log);
> true

markTrustedPeer¶

web3.shh.markTrustedPeer(enode, [callback])

Marks specific peer trusted, which will allow it to send historic (expired) messages.

Note

This function is not adding new nodes, the node needs to be an existing peer.

Parameters¶

String - Enode of the trusted peer.
Function - (optional) Optional callback, returns an error object as first parameter and the result as second.

Returns¶

Boolean - true on success, error on failure.

Example¶

web3.shh.markTrustedPeer()
.then(console.log);
> true

newKeyPair¶

web3.shh.newKeyPair([callback])

Generates a new public and private key pair for message decryption and encryption.

Parameters¶

Function - (optional) Optional callback, returns an error object as first parameter and the result as second.

Returns¶

String - Key ID on success and an error on failure.

Example¶

web3.shh.newKeyPair()
.then(console.log);
> "5e57b9ffc2387e18636e0a3d0c56b023264c16e78a2adcba1303cefc685e610f"

addPrivateKey¶

web3.shh.addPrivateKey(privateKey, [callback])

Stores a key pair derived from a private key, and returns its ID.

Parameters¶

String - The private key as HEX bytes to import.
Function - (optional) Optional callback, returns an error object as first parameter and the result as second.

Returns¶

String - Key ID on success and an error on failure.

Example¶

web3.shh.addPrivateKey('0x8bda3abeb454847b515fa9b404cede50b1cc63cfdeddd4999d074284b4c21e15')
.then(console.log);
> "3e22b9ffc2387e18636e0a3d0c56b023264c16e78a2adcba1303cefc685e610f"

deleteKeyPair¶

web3.shh.deleteKeyPair(id, [callback])

Deletes the specifies key if it exists.

Parameters¶

String - The key pair ID, returned by the creation functions (shh.newKeyPair and shh.addPrivateKey).
Function - (optional) Optional callback, returns an error object as first parameter and the result as second.

Returns¶

Boolean - true on success, error on failure.

Example¶

web3.shh.deleteKeyPair('3e22b9ffc2387e18636e0a3d0c56b023264c16e78a2adcba1303cefc685e610f')
.then(console.log);
> true

hasKeyPair¶

web3.shh.hasKeyPair(id, [callback])

Checks if the whisper node has a private key of a key pair matching the given ID.

Parameters¶

String - The key pair ID, returned by the creation functions (shh.newKeyPair and shh.addPrivateKey).
Function - (optional) Optional callback, returns an error object as first parameter and the result as second.

Returns¶

Boolean - true on if the key pair exist in the node, false if not. Error on failure.

Example¶

web3.shh.hasKeyPair('fe22b9ffc2387e18636e0a3d0c56b023264c16e78a2adcba1303cefc685e610f')
.then(console.log);
> true

getPublicKey¶

web3.shh.getPublicKey(id, [callback])

Returns the public key for a key pair ID.

Parameters¶

String - The key pair ID, returned by the creation functions (shh.newKeyPair and shh.addPrivateKey).
Function - (optional) Optional callback, returns an error object as first parameter and the result as second.

Returns¶

String - Public key on success and an error on failure.

Example¶

web3.shh.getPublicKey('3e22b9ffc2387e18636e0a3d0c56b023264c16e78a2adcba1303cefc685e610f')
.then(console.log);
> "0x04d1574d4eab8f3dde4d2dc7ed2c4d699d77cbbdd09167b8fffa099652ce4df00c4c6e0263eafe05007a46fdf0c8d32b11aeabcd3abbc7b2bc2bb967368a68e9c6"

getPrivateKey¶

web3.shh.getPrivateKey(id, [callback])

Returns the private key for a key pair ID.

Parameters¶

String - The key pair ID, returned by the creation functions (shh.newKeyPair and shh.addPrivateKey).
Function - (optional) Optional callback, returns an error object as first parameter and the result as second.

Returns¶

String - Private key on success and an error on failure.

Example¶

web3.shh.getPrivateKey('3e22b9ffc2387e18636e0a3d0c56b023264c16e78a2adcba1303cefc685e610f')
.then(console.log);
> "0x234234e22b9ffc2387e18636e0534534a3d0c56b0243567432453264c16e78a2adc"

newSymKey¶

web3.shh.newSymKey([callback])

Generates a random symmetric key and stores it under an ID, which is then returned. Will be used for encrypting and decrypting of messages where the sym key is known to both parties.

Parameters¶

Function - (optional) Optional callback, returns an error object as first parameter and the result as second.

Returns¶

String - Key ID on success and an error on failure.

Example¶

web3.shh.newSymKey()
.then(console.log);
> "cec94d139ff51d7df1d228812b90c23ec1f909afa0840ed80f1e04030bb681e4"

addSymKey¶

web3.shh.addSymKey(symKey, [callback])

Stores the key, and returns its ID.

Parameters¶

String - The raw key for symmetric encryption as HEX bytes.
Function - (optional) Optional callback, returns an error object as first parameter and the result as second.

Returns¶

String - Key ID on success and an error on failure.

Example¶

web3.shh.addSymKey('0x5e11b9ffc2387e18636e0a3d0c56b023264c16e78a2adcba1303cefc685e610f')
.then(console.log);
> "fea94d139ff51d7df1d228812b90c23ec1f909afa0840ed80f1e04030bb681e4"

generateSymKeyFromPassword¶

web3.shh.generateSymKeyFromPassword(password, [callback])

Generates the key from password, stores it, and returns its ID.

Parameters¶

String - A password to generate the sym key from.
Function - (optional) Optional callback, returns an error object as first parameter and the result as second.

Returns¶

Promise<string>|undefined - Returns the Key ID as Promise or undefined if a callback is defined.

Example¶

web3.shh.generateSymKeyFromPassword('Never use this password - password!')
.then(console.log);
> "2e57b9ffc2387e18636e0a3d0c56b023264c16e78a2adcba1303cefc685e610f"

hasSymKey¶

web3.shh.hasSymKey(id, [callback])

Checks if there is a symmetric key stored with the given ID.

Parameters¶

String - The key pair ID, returned by the creation functions (shh.newSymKey, shh.addSymKey or shh.generateSymKeyFromPassword).
Function - (optional) Optional callback, returns an error object as first parameter and the result as second.

Returns¶

Boolean - true on if the symmetric key exist in the node, false if not. Error on failure.

Example¶

web3.shh.hasSymKey('f6dcf21ed6a17bd78d8c4c63195ab997b3b65ea683705501eae82d32667adc92')
.then(console.log);
> true

getSymKey¶

web3.shh.getSymKey(id, [callback])

Returns the symmetric key associated with the given ID.

Parameters¶

String - The key pair ID, returned by the creation functions (shh.newKeyPair and shh.addPrivateKey).
Function - (optional) Optional callback, returns an error object as first parameter and the result as second.

Returns¶

String - The raw symmetric key on success and an error on failure.

Example¶

web3.shh.getSymKey('af33b9ffc2387e18636e0a3d0c56b023264c16e78a2adcba1303cefc685e610f')
.then(console.log);
> "0xa82a520aff70f7a989098376e48ec128f25f767085e84d7fb995a9815eebff0a"

deleteSymKey¶

web3.shh.deleteSymKey(id, [callback])

Deletes the symmetric key associated with the given ID.

Parameters¶

String - The key pair ID, returned by the creation functions (shh.newKeyPair and shh.addPrivateKey).
Function - (optional) Optional callback, returns an error object as first parameter and the result as second.

Returns¶

Boolean - true on if the symmetric key was deleted, error on failure.

Example¶

web3.shh.deleteSymKey('bf31b9ffc2387e18636e0a3d0c56b023264c16e78a2adcba1303cefc685e610f')
.then(console.log);
> true

post¶

web3.shh.post(object [, callback])

This method should be called, when we want to post whisper a message to the network.

Parameters¶

Object - The post object:
- symKeyID - String (optional): ID of symmetric key for message encryption (Either symKeyID or pubKey must be present. Can not be both.).
- pubKey - String (optional): The public key for message encryption (Either symKeyID or pubKey must be present. Can not be both.).
- sig - String (optional): The ID of the signing key.
- ttl - Number: Time-to-live in seconds.
- topic - String: 4 Bytes (mandatory when key is symmetric): Message topic.
- payload - String: The payload of the message to be encrypted.
- padding - Number (optional): Padding (byte array of arbitrary length).
- powTime - Number (optional)?: Maximal time in seconds to be spent on proof of work.
- powTarget - Number (optional)?: Minimal PoW target required for this message.
- targetPeer - Number (optional): Peer ID (for peer-to-peer message only).
callback - Function: (optional) Optional callback, returns an error object as first parameter and the result as second.

Returns¶

Promise - returns a promise. Upon success, the then function will be passed a string representing the hash of the sent message. On error, the catch function will be passed a string containing the reason for the error.

Example¶

var identities = [];
var subscription = null;

Promise.all([
    web3.shh.newSymKey().then((id) => {identities.push(id);}),
    web3.shh.newKeyPair().then((id) => {identities.push(id);})

]).then(() => {

    // will receive also its own message send, below
    subscription = shh.subscribe("messages", {
        symKeyID: identities[0],
        topics: ['0xffaadd11']
    }).on('data', console.log);

}).then(() => {
   web3.shh.post({
        symKeyID: identities[0], // encrypts using the sym key ID
        sig: identities[1], // signs the message using the keyPair ID
        ttl: 10,
        topic: '0xffaadd11',
        payload: '0xffffffdddddd1122',
        powTime: 3,
        powTarget: 0.5
    }).then(h => console.log(`Message with hash ${h} was successfuly sent`))
    .catch(err => console.log("Error: ", err));
});

subscribe¶

web3.shh.subscribe('messages', options [, callback])

Subscribe for incoming whisper messages.

Parameters¶

"messages" - String: Type of the subscription.
Object - The subscription options:
- symKeyID - String: ID of symmetric key for message decryption.
- privateKeyID - String: ID of private (asymmetric) key for message decryption.
- sig - String (optional): Public key of the signature, to verify.
- topics- Array (optional when “privateKeyID” key is given): Filters messages by this topic(s). Each topic must be a 4 bytes HEX string.
- minPow - Number (optional): Minimal PoW requirement for incoming messages.
- allowP2P - Boolean (optional): Indicates if this filter allows processing of direct peer-to-peer messages (which are not to be forwarded any further, because they might be expired). This might be the case in some very rare cases, e.g. if you intend to communicate to MailServers, etc.
callback - Function: (optional) Optional callback, returns an error object as first parameter and the result as second. Will be called for each incoming subscription, and the subscription itself as 3 parameter.

Notification Returns¶

Object - The incoming message:

hash - String: Hash of the enveloped message.

sig - String: Public key which signed this message.

recipientPublicKey - String: The recipients public key.

timestamp - String: Unix timestamp of the message genertion.

ttl - Number: Time-to-live in seconds.

topic - String: 4 Bytes HEX string message topic.

payload - String: Decrypted payload.

padding - Number: Optional padding (byte array of arbitrary length).

pow - Number: Proof of work value.

Example¶

web3.shh.subscribe('messages', {
    symKeyID: 'bf31b9ffc2387e18636e0a3d0c56b023264c16e78a2adcba1303cefc685e610f',
    sig: '0x04d1574d4eab8f3dde4d2dc7ed2c4d699d77cbbdd09167b8fffa099652ce4df00c4c6e0263eafe05007a46fdf0c8d32b11aeabcd3abbc7b2bc2bb967368a68e9c6',
    ttl: 20,
    topics: ['0xffddaa11'],
    minPow: 0.8,
}, function(error, message, subscription){

    console.log(message);
    > {
        "hash": "0x4158eb81ad8e30cfcee67f20b1372983d388f1243a96e39f94fd2797b1e9c78e",
        "padding": "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",
        "payload": "0xdeadbeaf",
        "pow": 0.5371803278688525,
        "recipientPublicKey": null,
        "sig": null,
        "timestamp": 1496991876,
        "topic": "0x01020304",
        "ttl": 50
    }
})
// or
.on('data', function(message){ ... });

clearSubscriptions¶

web3.shh.clearSubscriptions()

Resets subscriptions.

Note

This will not reset subscriptions from other packages like web3-eth, as they use their own requestManager.

Parameters¶

Boolean: If true it keeps the "syncing" subscription.

Returns¶

Boolean

Example¶

web3.shh.subscribe('messages', {...} ,function(){ ... });

...

web3.shh.clearSubscriptions();

newMessageFilter¶

web3.shh.newMessageFilter(options)

Create a new filter within the node. This filter can be used to poll for new messages that match the set of criteria.

Parameters¶

Object: See web3.shh.subscribe() options for details.

Returns¶

String: The filter ID.

Example¶

web3.shh.newMessageFilter()
.then(console.log);
> "2b47fbafb3cce24570812a82e6e93cd9e2551bbc4823f6548ff0d82d2206b326"

deleteMessageFilter¶

web3.shh.deleteMessageFilter(id)

Deletes a message filter in the node.

Parameters¶

String: The filter ID created with shh.newMessageFilter().

Returns¶

Boolean: true on success, error on failure.

Example¶

web3.shh.deleteMessageFilter('2b47fbafb3cce24570812a82e6e93cd9e2551bbc4823f6548ff0d82d2206b326')
.then(console.log);
> true

getFilterMessages¶

web3.shh.getFilterMessages(id)

Retrieve messages that match the filter criteria and are received between the last time this function was called and now.

Parameters¶

String: The filter ID created with shh.newMessageFilter().

Returns¶

Array: Returns an array of message objects like web3.shh.subscribe() notification returns

Example¶

web3.shh.getFilterMessages('2b47fbafb3cce24570812a82e6e93cd9e2551bbc4823f6548ff0d82d2206b326')
.then(console.log);
> [{
    "hash": "0x4158eb81ad8e30cfcee67f20b1372983d388f1243a96e39f94fd2797b1e9c78e",
    "padding": "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",
    "payload": "0xdeadbeaf",
    "pow": 0.5371803278688525,
    "recipientPublicKey": null,
    "sig": null,
    "timestamp": 1496991876,
    "topic": "0x01020304",
    "ttl": 50
},{...}]

web3.utils¶

This package provides utility functions for Ethereum dapps and other web3.js packages.

Bloom Filters¶

What are bloom filters?¶

A Bloom filter is a probabilistic, space-efficient data structure used for fast checks of set membership. That probably doesn’t mean much to you yet, and so let’s explore how bloom filters might be used.

Imagine that we have some large set of data, and we want to be able to quickly test if some element is currently in that set. The naive way of checking might be to query the set to see if our element is in there. That’s probably fine if our data set is relatively small. Unfortunately, if our data set is really big, this search might take a while. Luckily, we have tricks to speed things up in the ethereum world!

A bloom filter is one of these tricks. The basic idea behind the Bloom filter is to hash each new element that goes into the data set, take certain bits from this hash, and then use those bits to fill in parts of a fixed-size bit array (e.g. set certain bits to 1). This bit array is called a bloom filter.

Later, when we want to check if an element is in the set, we simply hash the element and check that the right bits are in the bloom filter. If at least one of the bits is 0, then the element definitely isn’t in our data set! If all of the bits are 1, then the element might be in the data set, but we need to actually query the database to be sure. So we might have false positives, but we’ll never have false negatives. This can greatly reduce the number of database queries we have to make.

Real Life Example

A ethereum real life example in where this is useful is if you want to update a users balance on every new block so it stays as close to real time as possible. Without using a bloom filter on every new block you would have to force the balances even if that user may not of had any activity within that block. But if you use the logBlooms from the block you can test the bloom filter against the users ethereum address before you do any more slow operations, this will dramatically decrease the amount of calls you do as you will only be doing those extra operations if that ethereum address is within that block (minus the false positives outcome which will be negligible). This will be highly performant for your app.

Functions¶

Note

Please raise any issues here

randomHex¶

web3.utils.randomHex(size)

The randomHex library to generate cryptographically strong pseudo-random HEX strings from a given byte size.

Parameters¶

size - Number: The byte size for the HEX string, e.g. 32 will result in a 32 bytes HEX string with 64 characters preficed with “0x”.

Returns¶

String: The generated random HEX string.

Example¶

web3.utils.randomHex(32)
> "0xa5b9d60f32436310afebcfda832817a68921beb782fabf7915cc0460b443116a"

web3.utils.randomHex(4)
> "0x6892ffc6"

web3.utils.randomHex(2)
> "0x99d6"

web3.utils.randomHex(1)
> "0x9a"

web3.utils.randomHex(0)
> "0x"

_¶

web3.utils._()

The underscore library for many convenience JavaScript functions.

See the underscore API reference for details.

Example¶

var _ = web3.utils._;

_.union([1,2],[3]);
> [1,2,3]

_.each({my: 'object'}, function(value, key){ ... })

...

BN¶

web3.utils.BN(mixed)

The BN.js library for calculating with big numbers in JavaScript. See the BN.js documentation for details.

Note

For safe conversion of many types, incl BigNumber.js use utils.toBN

Parameters¶

mixed - String|Number: A number, number string or HEX string to convert to a BN object.

Returns¶

Object: The BN.js instance.

Example¶

var BN = web3.utils.BN;

new BN(1234).toString();
> "1234"

new BN('1234').add(new BN('1')).toString();
> "1235"

new BN('0xea').toString();
> "234"

isBN¶

web3.utils.isBN(bn)

Checks if a given value is a BN.js instance.

Parameters¶

bn - Object: An BN.js instance.

Returns¶

Boolean

Example¶

var number = new BN(10);

web3.utils.isBN(number);
> true

isBigNumber¶

web3.utils.isBigNumber(bignumber)

Checks if a given value is a BigNumber.js instance.

Parameters¶

bignumber - Object: A BigNumber.js instance.

Returns¶

Boolean

Example¶

var number = new BigNumber(10);

web3.utils.isBigNumber(number);
> true

sha3¶

web3.utils.sha3(string)
web3.utils.keccak256(string) // ALIAS

Will calculate the sha3 of the input.

Note

To mimic the sha3 behaviour of solidity use soliditySha3

Parameters¶

string - String: A string to hash.

Returns¶

String: the result hash.

Example¶

web3.utils.sha3('234'); // taken as string
> "0xc1912fee45d61c87cc5ea59dae311904cd86b84fee17cc96966216f811ce6a79"

web3.utils.sha3(new BN('234'));
> "0xbc36789e7a1e281436464229828f817d6612f7b477d66591ff96a9e064bcc98a"

web3.utils.sha3(234);
> null // can't calculate the has of a number

web3.utils.sha3(0xea); // same as above, just the HEX representation of the number
> null

web3.utils.sha3('0xea'); // will be converted to a byte array first, and then hashed
> "0x2f20677459120677484f7104c76deb6846a2c071f9b3152c103bb12cd54d1a4a"

soliditySha3¶

web3.utils.soliditySha3(param1 [, param2, ...])

Will calculate the sha3 of given input parameters in the same way solidity would. This means arguments will be ABI converted and tightly packed before being hashed.

Parameters¶

paramX - Mixed: Any type, or an object with {type: 'uint', value: '123456'} or {t: 'bytes', v: '0xfff456'}. Basic types are autodetected as follows:
- String non numerical UTF-8 string is interpreted as string.
- String|Number|BN|HEX positive number is interpreted as uint256.
- String|Number|BN negative number is interpreted as int256.
- Boolean as bool.
- String HEX string with leading 0x is interpreted as bytes.
- HEX HEX number representation is interpreted as uint256.

Returns¶

String: the result hash.

Example¶

web3.utils.soliditySha3('234564535', '0xfff23243', true, -10);
// auto detects:        uint256,      bytes,     bool,   int256
> "0x3e27a893dc40ef8a7f0841d96639de2f58a132be5ae466d40087a2cfa83b7179"


web3.utils.soliditySha3('Hello!%'); // auto detects: string
> "0x661136a4267dba9ccdf6bfddb7c00e714de936674c4bdb065a531cf1cb15c7fc"


web3.utils.soliditySha3('234'); // auto detects: uint256
> "0x61c831beab28d67d1bb40b5ae1a11e2757fa842f031a2d0bc94a7867bc5d26c2"

web3.utils.soliditySha3(0xea); // same as above
> "0x61c831beab28d67d1bb40b5ae1a11e2757fa842f031a2d0bc94a7867bc5d26c2"

web3.utils.soliditySha3(new BN('234')); // same as above
> "0x61c831beab28d67d1bb40b5ae1a11e2757fa842f031a2d0bc94a7867bc5d26c2"

web3.utils.soliditySha3({type: 'uint256', value: '234'})); // same as above
> "0x61c831beab28d67d1bb40b5ae1a11e2757fa842f031a2d0bc94a7867bc5d26c2"

web3.utils.soliditySha3({t: 'uint', v: new BN('234')})); // same as above
> "0x61c831beab28d67d1bb40b5ae1a11e2757fa842f031a2d0bc94a7867bc5d26c2"


web3.utils.soliditySha3('0x407D73d8a49eeb85D32Cf465507dd71d507100c1');
> "0x4e8ebbefa452077428f93c9520d3edd60594ff452a29ac7d2ccc11d47f3ab95b"

web3.utils.soliditySha3({t: 'bytes', v: '0x407D73d8a49eeb85D32Cf465507dd71d507100c1'});
> "0x4e8ebbefa452077428f93c9520d3edd60594ff452a29ac7d2ccc11d47f3ab95b" // same result as above


web3.utils.soliditySha3({t: 'address', v: '0x407D73d8a49eeb85D32Cf465507dd71d507100c1'});
> "0x4e8ebbefa452077428f93c9520d3edd60594ff452a29ac7d2ccc11d47f3ab95b" // same as above, but will do a checksum check, if its multi case


web3.utils.soliditySha3({t: 'bytes32', v: '0x407D73d8a49eeb85D32Cf465507dd71d507100c1'});
> "0x3c69a194aaf415ba5d6afca734660d0a3d45acdc05d54cd1ca89a8988e7625b4" // different result as above


web3.utils.soliditySha3({t: 'string', v: 'Hello!%'}, {t: 'int8', v:-23}, {t: 'address', v: '0x85F43D8a49eeB85d32Cf465507DD71d507100C1d'});
> "0xa13b31627c1ed7aaded5aecec71baf02fe123797fffd45e662eac8e06fbe4955"

isHex¶

web3.utils.isHex(hex)

Checks if a given string is a HEX string.

Parameters¶

hex - String|HEX: The given HEX string.

Returns¶

Boolean

Example¶

web3.utils.isHex('0xc1912');
> true

web3.utils.isHex(0xc1912);
> true

web3.utils.isHex('c1912');
> true

web3.utils.isHex(345);
> true // this is tricky, as 345 can be a a HEX representation or a number, be careful when not having a 0x in front!

web3.utils.isHex('0xZ1912');
> false

web3.utils.isHex('Hello');
> false

isHexStrict¶

web3.utils.isHexStrict(hex)

Checks if a given string is a HEX string. Difference to web3.utils.isHex() is that it expects HEX to be prefixed with 0x.

Parameters¶

hex - String|HEX: The given HEX string.

Returns¶

Boolean

Example¶

web3.utils.isHexStrict('0xc1912');
> true

web3.utils.isHexStrict(0xc1912);
> false

web3.utils.isHexStrict('c1912');
> false

web3.utils.isHexStrict(345);
> false // this is tricky, as 345 can be a a HEX representation or a number, be careful when not having a 0x in front!

web3.utils.isHexStrict('0xZ1912');
> false

web3.utils.isHex('Hello');
> false

isAddress¶

web3.utils.isAddress(address)

Checks if a given string is a valid Ethereum address. It will also check the checksum, if the address has upper and lowercase letters.

Parameters¶

address - String: An address string.

Returns¶

Boolean

Example¶

web3.utils.isAddress('0xc1912fee45d61c87cc5ea59dae31190fffff232d');
> true

web3.utils.isAddress('c1912fee45d61c87cc5ea59dae31190fffff232d');
> true

web3.utils.isAddress('0XC1912FEE45D61C87CC5EA59DAE31190FFFFF232D');
> true // as all is uppercase, no checksum will be checked

web3.utils.isAddress('0xc1912fEE45d61C87Cc5EA59DaE31190FFFFf232d');
> true

web3.utils.isAddress('0xC1912fEE45d61C87Cc5EA59DaE31190FFFFf232d');
> false // wrong checksum

toChecksumAddress¶

web3.utils.toChecksumAddress(address)

Will convert an upper or lowercase Ethereum address to a checksum address.

Parameters¶

address - String: An address string.

Returns¶

String: The checksum address.

Example¶

web3.utils.toChecksumAddress('0xc1912fee45d61c87cc5ea59dae31190fffff2323');
> "0xc1912fEE45d61C87Cc5EA59DaE31190FFFFf232d"

web3.utils.toChecksumAddress('0XC1912FEE45D61C87CC5EA59DAE31190FFFFF232D');
> "0xc1912fEE45d61C87Cc5EA59DaE31190FFFFf232d" // same as above

checkAddressChecksum¶

web3.utils.checkAddressChecksum(address)

Checks the checksum of a given address. Will also return false on non-checksum addresses.

Parameters¶

address - String: An address string.

Returns¶

Boolean: true when the checksum of the address is valid, false if its not a checksum address, or the checksum is invalid.

Example¶

web3.utils.checkAddressChecksum('0xc1912fEE45d61C87Cc5EA59DaE31190FFFFf232d');
> true

toHex¶

web3.utils.toHex(mixed)

Will auto convert any given value to HEX. Number strings will interpreted as numbers. Text strings will be interpreted as UTF-8 strings.

Parameters¶

mixed - String|Number|BN|BigNumber: The input to convert to HEX.

Returns¶

String: The resulting HEX string.

Example¶

web3.utils.toHex('234');
> "0xea"

web3.utils.toHex(234);
> "0xea"

web3.utils.toHex(new BN('234'));
> "0xea"

web3.utils.toHex(new BigNumber('234'));
> "0xea"

web3.utils.toHex('I have 100€');
> "0x49206861766520313030e282ac"

toBN¶

web3.utils.toBN(number)

Will safely convert any given value (including BigNumber.js instances) into a BN.js instance, for handling big numbers in JavaScript.

Note

For just the BN.js class use utils.BN

Parameters¶

number - String|Number|HEX: Number to convert to a big number.

Returns¶

Object: The BN.js instance.

Example¶

web3.utils.toBN(1234).toString();
> "1234"

web3.utils.toBN('1234').add(web3.utils.toBN('1')).toString();
> "1235"

web3.utils.toBN('0xea').toString();
> "234"

hexToNumberString¶

web3.utils.hexToNumberString(hex)

Returns the number representation of a given HEX value as a string.

Parameters¶

hexString - String|HEX: A string to hash.

Returns¶

String: The number as a string.

Example¶

web3.utils.hexToNumberString('0xea');
> "234"

hexToNumber¶

web3.utils.hexToNumber(hex)
web3.utils.toDecimal(hex) // ALIAS, deprecated

Returns the number representation of a given HEX value.

Note

This is not useful for big numbers, rather use utils.toBN instead.

Parameters¶

hexString - String|HEX: A string to hash.

Returns¶

Number

Example¶

web3.utils.hexToNumber('0xea');
> 234

numberToHex¶

web3.utils.numberToHex(number)
web3.utils.fromDecimal(number) // ALIAS, deprecated

Returns the HEX representation of a given number value.

Parameters¶

number - String|Number|BN|BigNumber: A number as string or number.

Returns¶

String: The HEX value of the given number.

Example¶

web3.utils.numberToHex('234');
> '0xea'

hexToUtf8¶

web3.utils.hexToUtf8(hex)
web3.utils.hexToString(hex) // ALIAS
web3.utils.toUtf8(hex) // ALIAS, deprecated

Returns the UTF-8 string representation of a given HEX value.

Parameters¶

hex - String: A HEX string to convert to a UTF-8 string.

Returns¶

String: The UTF-8 string.

Example¶

web3.utils.hexToUtf8('0x49206861766520313030e282ac');
> "I have 100€"

hexToAscii¶

web3.utils.hexToAscii(hex)
web3.utils.toAscii(hex) // ALIAS, deprecated

Returns the ASCII string representation of a given HEX value.

Parameters¶

hex - String: A HEX string to convert to a ASCII string.

Returns¶

String: The ASCII string.

Example¶

web3.utils.hexToAscii('0x4920686176652031303021');
> "I have 100!"

utf8ToHex¶

web3.utils.utf8ToHex(string)
web3.utils.stringToHex(string) // ALIAS
web3.utils.fromUtf8(string) // ALIAS, deprecated

Returns the HEX representation of a given UTF-8 string.

Parameters¶

string - String: A UTF-8 string to convert to a HEX string.

Returns¶

String: The HEX string.

Example¶

web3.utils.utf8ToHex('I have 100€');
> "0x49206861766520313030e282ac"

asciiToHex¶

web3.utils.asciiToHex(string)
web3.utils.fromAscii(string) // ALIAS, deprecated

Returns the HEX representation of a given ASCII string.

Parameters¶

string - String: A ASCII string to convert to a HEX string.

Returns¶

String: The HEX string.

Example¶

web3.utils.asciiToHex('I have 100!');
> "0x4920686176652031303021"

hexToBytes¶

web3.utils.hexToBytes(hex)

Returns a byte array from the given HEX string.

Parameters¶

hex - String|HEX: A HEX to convert.

Returns¶

Array: The byte array.

Example¶

web3.utils.hexToBytes('0x000000ea');
> [ 0, 0, 0, 234 ]

web3.utils.hexToBytes(0x000000ea);
> [ 234 ]

bytesToHex¶

web3.utils.bytesToHex(byteArray)

Returns a HEX string from a byte array.

Parameters¶

byteArray - Array: A byte array to convert.

Returns¶

String: The HEX string.

Example¶

web3.utils.bytesToHex([ 72, 101, 108, 108, 111, 33, 36 ]);
> "0x48656c6c6f2125"

toWei¶

web3.utils.toWei(number [, unit])

Converts any ether value value into wei.

Note

“wei” are the smallest ethere unit, and you should always make calculations in wei and convert only for display reasons.

Parameters¶

number - String|BN: The value.
unit - String (optional, defaults to "ether"): The ether to convert from. Possible units are:
- noether: ‘0’
- wei: ‘1’
- kwei: ‘1000’
- Kwei: ‘1000’
- babbage: ‘1000’
- femtoether: ‘1000’
- mwei: ‘1000000’
- Mwei: ‘1000000’
- lovelace: ‘1000000’
- picoether: ‘1000000’
- gwei: ‘1000000000’
- Gwei: ‘1000000000’
- shannon: ‘1000000000’
- nanoether: ‘1000000000’
- nano: ‘1000000000’
- szabo: ‘1000000000000’
- microether: ‘1000000000000’
- micro: ‘1000000000000’
- finney: ‘1000000000000000’
- milliether: ‘1000000000000000’
- milli: ‘1000000000000000’
- ether: ‘1000000000000000000’
- kether: ‘1000000000000000000000’
- grand: ‘1000000000000000000000’
- mether: ‘1000000000000000000000000’
- gether: ‘1000000000000000000000000000’
- tether: ‘1000000000000000000000000000000’

Returns¶

String|BN: If a string is given it returns a number string, otherwise a BN.js instance.

Example¶

web3.utils.toWei('1', 'ether');
> "1000000000000000000"

web3.utils.toWei('1', 'finney');
> "1000000000000000"

web3.utils.toWei('1', 'szabo');
> "1000000000000"

web3.utils.toWei('1', 'shannon');
> "1000000000"

fromWei¶

web3.utils.fromWei(number [, unit])

Converts any wei value into a ether value.

Note

“wei” are the smallest ethere unit, and you should always make calculations in wei and convert only for display reasons.

Parameters¶

number - String|BN: The value in wei.
unit - String (optional, defaults to "ether"): The ether to convert to. Possible units are:
- noether: ‘0’
- wei: ‘1’
- kwei: ‘1000’
- Kwei: ‘1000’
- babbage: ‘1000’
- femtoether: ‘1000’
- mwei: ‘1000000’
- Mwei: ‘1000000’
- lovelace: ‘1000000’
- picoether: ‘1000000’
- gwei: ‘1000000000’
- Gwei: ‘1000000000’
- shannon: ‘1000000000’
- nanoether: ‘1000000000’
- nano: ‘1000000000’
- szabo: ‘1000000000000’
- microether: ‘1000000000000’
- micro: ‘1000000000000’
- finney: ‘1000000000000000’
- milliether: ‘1000000000000000’
- milli: ‘1000000000000000’
- ether: ‘1000000000000000000’
- kether: ‘1000000000000000000000’
- grand: ‘1000000000000000000000’
- mether: ‘1000000000000000000000000’
- gether: ‘1000000000000000000000000000’
- tether: ‘1000000000000000000000000000000’

Returns¶

String: It always returns a string number.

Example¶

web3.utils.fromWei('1', 'ether');
> "0.000000000000000001"

web3.utils.fromWei('1', 'finney');
> "0.000000000000001"

web3.utils.fromWei('1', 'szabo');
> "0.000000000001"

web3.utils.fromWei('1', 'shannon');
> "0.000000001"

unitMap¶

web3.utils.unitMap

Shows all possible ether value and their amount in wei.

Return value¶

Object with the following properties:
- noether: ‘0’
- wei: ‘1’
- kwei: ‘1000’
- Kwei: ‘1000’
- babbage: ‘1000’
- femtoether: ‘1000’
- mwei: ‘1000000’
- Mwei: ‘1000000’
- lovelace: ‘1000000’
- picoether: ‘1000000’
- gwei: ‘1000000000’
- Gwei: ‘1000000000’
- shannon: ‘1000000000’
- nanoether: ‘1000000000’
- nano: ‘1000000000’
- szabo: ‘1000000000000’
- microether: ‘1000000000000’
- micro: ‘1000000000000’
- finney: ‘1000000000000000’
- milliether: ‘1000000000000000’
- milli: ‘1000000000000000’
- ether: ‘1000000000000000000’
- kether: ‘1000000000000000000000’
- grand: ‘1000000000000000000000’
- mether: ‘1000000000000000000000000’
- gether: ‘1000000000000000000000000000’
- tether: ‘1000000000000000000000000000000’

Example¶

web3.utils.unitMap
> {
    noether: '0',
    wei:        '1',
    kwei:       '1000',
    Kwei:       '1000',
    babbage:    '1000',
    femtoether: '1000',
    mwei:       '1000000',
    Mwei:       '1000000',
    lovelace:   '1000000',
    picoether:  '1000000',
    gwei:       '1000000000',
    Gwei:       '1000000000',
    shannon:    '1000000000',
    nanoether:  '1000000000',
    nano:       '1000000000',
    szabo:      '1000000000000',
    microether: '1000000000000',
    micro:      '1000000000000',
    finney:     '1000000000000000',
    milliether: '1000000000000000',
    milli:      '1000000000000000',
    ether:      '1000000000000000000',
    kether:     '1000000000000000000000',
    grand:      '1000000000000000000000',
    mether:     '1000000000000000000000000',
    gether:     '1000000000000000000000000000',
    tether:     '1000000000000000000000000000000'
}

padLeft¶

web3.utils.padLeft(string, characterAmount [, sign])
web3.utils.leftPad(string, characterAmount [, sign]) // ALIAS

Adds a padding on the left of a string, Useful for adding paddings to HEX strings.

Parameters¶

string - String: The string to add padding on the left.
characterAmount - Number: The number of characters the total string should have.
sign - String (optional): The character sign to use, defaults to "0".

Returns¶

String: The padded string.

Example¶

web3.utils.padLeft('0x3456ff', 20);
> "0x000000000000003456ff"

web3.utils.padLeft(0x3456ff, 20);
> "0x000000000000003456ff"

web3.utils.padLeft('Hello', 20, 'x');
> "xxxxxxxxxxxxxxxHello"

padRight¶

web3.utils.padRight(string, characterAmount [, sign])
web3.utils.rightPad(string, characterAmount [, sign]) // ALIAS

Adds a padding on the right of a string, Useful for adding paddings to HEX strings.

Parameters¶

string - String: The string to add padding on the right.
characterAmount - Number: The number of characters the total string should have.
sign - String (optional): The character sign to use, defaults to "0".

Returns¶

String: The padded string.

Example¶

web3.utils.padRight('0x3456ff', 20);
> "0x3456ff00000000000000"

web3.utils.padRight(0x3456ff, 20);
> "0x3456ff00000000000000"

web3.utils.padRight('Hello', 20, 'x');
> "Helloxxxxxxxxxxxxxxx"

toTwosComplement¶

web3.utils.toTwosComplement(number)

Converts a negative numer into a two’s complement.

Parameters¶

number - Number|String|BigNumber: The number to convert.

Returns¶

String: The converted hex string.

Example¶

web3.utils.toTwosComplement('-1');
> "0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff"

web3.utils.toTwosComplement(-1);
> "0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff"

web3.utils.toTwosComplement('0x1');
> "0x0000000000000000000000000000000000000000000000000000000000000001"

web3.utils.toTwosComplement(-15);
> "0xfffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff1"

web3.utils.toTwosComplement('-0x1');
> "0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff"