Note

This documentation is work in progress and web3.js 1.0 is not yet released! You can find the current documentation for web3 0.x.x at github.com/ethereum/wiki/wiki/JavaScript-API.

Web3

Class

This’s main class of anything related Ethereum.

var Web3 = require('web3');

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

Web3.modules

Property of Web3 class
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 modules:
  • Eth - Function: the Eth module for interacting with the Ethereum network see web3.eth for more.
  • Net - Function: the Net module for interacting with network properties see web3.eth.net for more.
  • Personal - Function: the Personal module for interacting with the Ethereum accounts see web3.eth.personal for more.
  • Shh - Function: the Shh module for interacting with the whisper protocol see web3.shh for more.
  • Bzz - Function: the Bzz module for interacting with the swarm network see web3.bzz for more.

Example

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

web3 object

The instance of Web3

The web3.js object 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

Property of Web3 class and instance of Web3
Web3.version
web3.version

Contains the version of the web3 container object.

Returns

String: The current version.

Example

web3.version;
> "1.0.0"

utils

Property of Web3 class and instance of Web3
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

  1. 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

  1. 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 {...},
    ...
}