Note

This documentation is under construction and the web3.js 1.0 stable version isn’t released. If your using a version v0.x.x of web3.js then please have a look at github.com/ethereum/wiki/wiki/JavaScript-API.

Glossary

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
}]