web3.js - Ethereum JavaScript API
This is the Ethereum JavaScript API
which connects to the Generic JSON RPC spec.
You need to run a local or remote Ethereum node to use this library.
Please read the documentation for more.
Installation
Node
npm install web3
Yarn
yarn add web3
Meteor
Note: works only in the Browser for now. (PR welcome).
meteor add ethereum:web3
In the Browser
Use the prebuild dist/web3.min.js
, or
build using the web3.js repository:
npm run-script build
Then include dist/web3.js
in your html file.
This will expose Web3
on the window object.
Usage
var Web3 = require('web3');
var web3 = new Web3('ws://localhost:8546');
console.log(web3);
> {
eth: ... ,
shh: ... ,
utils: ...,
...
}
Additionally you can set a provider using web3.setProvider()
(e.g. WebsocketProvider):
web3.setProvider('ws://localhost:8546');
web3.setProvider(new Web3.providers.WebsocketProvider('ws://localhost:8546'));
There you go, now you can use it:
web3.eth.getAccounts()
.then(console.log);
Usage with TypeScript
Type definitions are maintained at DefinitelyTyped by others. You can install them with:
npm install --dev @types/web3.js
You might need to install type definitions for bignumber.js
and lodash
too.
And then use web3.js
as follows:
import Web3 = require("web3");
const web3 = new Web3("ws://localhost:8546");
Please note: We do not support TypeScript ourselves. If you have any issue with TypeScript and web3.js
do not create an issue here. Go over to DefinitelyTyped and do it there.
Documentation
Documentation can be found at read the docs.
Building
Requirements
sudo apt-get update
sudo apt-get install nodejs
sudo apt-get install npm
Building (gulp)
Build only the web3.js package
npm run-script build
Or build all sub packages as well:
npm run-script build-all
This will put all the browser build files into the dist
folder.
Testing (mocha)
npm test
Contributing
- All contributions have to go into develop, or the 1.0 branch
- Please follow the code style of the other files, we use 4 spaces as tabs.
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