web3
Advanced tools
Package description
The web3 npm package is a collection of libraries that allow you to interact with a local or remote Ethereum node, using HTTP, IPC, or WebSocket. It provides functionalities for interacting with smart contracts, sending transactions, and querying blockchain data.
Connecting to an Ethereum Node
This feature allows you to connect to an Ethereum node using an HTTP provider. You can replace the URL with your own node's URL or use a service like Infura.
const Web3 = require('web3');
const web3 = new Web3('https://mainnet.infura.io/v3/YOUR_INFURA_PROJECT_ID');Interacting with Smart Contracts
This feature allows you to interact with smart contracts deployed on the Ethereum blockchain. You need the contract's ABI and address to create a contract instance and call its methods.
const contractABI = [/* ABI array */];
const contractAddress = '0xYourContractAddress';
const contract = new web3.eth.Contract(contractABI, contractAddress);
contract.methods.yourMethod().call().then(console.log);Sending Transactions
This feature allows you to send transactions on the Ethereum network. You need the sender's account address and private key to sign and send the transaction.
const account = '0xYourAccountAddress';
const privateKey = 'your_private_key';
const tx = {
to: '0xRecipientAddress',
value: web3.utils.toWei('0.1', 'ether'),
gas: 2000000
};
web3.eth.accounts.signTransaction(tx, privateKey).then(signed => {
web3.eth.sendSignedTransaction(signed.rawTransaction)
.on('receipt', console.log);
});Querying Blockchain Data
This feature allows you to query data from the blockchain, such as retrieving the latest block information.
web3.eth.getBlock('latest').then(console.log);The ethers.js library aims to be a complete and compact library for interacting with the Ethereum Blockchain and its ecosystem. It provides similar functionalities to web3, such as connecting to Ethereum nodes, interacting with smart contracts, and sending transactions. Ethers.js is known for its smaller size and better documentation.
Truffle is a development environment, testing framework, and asset pipeline for Ethereum. While it provides some overlapping functionalities with web3, such as interacting with smart contracts, it is more focused on the development and deployment of smart contracts.
Embark is a framework for serverless Decentralized Applications using Ethereum, IPFS, and other platforms. It provides functionalities for smart contract management, decentralized storage, and communication, making it a more comprehensive solution compared to web3.
Readme
This is the Ethereum compatible JavaScript API which implements the Generic JSON RPC spec. It's available on npm as a node module, for bower and component as an embeddable js and as a meteor.js package.
You need to run a local ethrereum node to use this library.
$ npm install web3
$ meteor add ethereum:web3
Bower
$ bower install web3
Component
$ component install ethereum/web3.js
ethereum.min.js in your html file. (not required for the meteor package)Use the web3 object directly from global namespace:
console.log(web3); // {eth: .., shh: ...} // it's here!
Set a provider (QtSyncProvider, HttpProvider)
web3.setProvider(new web3.providers.HttpProvider('http://localhost:8545'));
There you go, now you can use it:
var coinbase = web3.eth.coinbase;
var balance = web3.eth.getBalance(coinbase);
For another example see example/index.html.
sudo apt-get update
sudo apt-get install nodejs
sudo apt-get install npm
sudo apt-get install nodejs-legacy
npm run-script build
npm test
Karma allows testing within one or several browsers.
npm run-script karma # default browsers are Chrome and Firefox
npm run-script karma -- --browsers="Chrome,Safari" # custom browsers
Please note this repo is in it's early stage.
If you'd like to run a Http ethereum node check out cpp-ethereum.
Install ethereum and spawn a node:
eth -j
FAQs
Ethereum JavaScript API
The npm package web3 receives a total of 347,189 weekly downloads. As such, web3 popularity was classified as popular.
We found that web3 demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 4 open source maintainers collaborating on the project.
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