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Web3 Chain Network

web3.js is a JavaScript library that allows developers to interact with EVM-compatible blockchain networks.

You can use web3.js to interact with smart contracts deployed on the Chain network.

Install​

To install web3.js run the following command:

npm install web3

Setup​

Before you can start using web3.js, you need to import it into your project.

Add the following line of code to the top of your file to import web3.js:

//web3.js v1
const Web3 = require('web3');

//web3.js v4
const { Web3 } = require('web3');

Connecting to Chain​

You can connect to Chain by instantiating a new web3.js Web3 object with a RPC URL of the Chain network:

const { Web3 } = require('web3');

const web3 = new Web3('https://mainnet.zentachain.io');
info

To alternatively connect to Chain Sepolia (testnet), change the above URL from https://mainnet.zentachain.io to https://rpc-sepolia.zentachain.io.

Accessing data​

Once you have created a provider, you can use it to read data from the Chain network.

For example, you can use the getBlockNumber method to get the latest block:

async function getLatestBlock(address) {
  const latestBlock = await web3.eth.getBlockNumber();
  console.log(latestBlock.toString());
}

Deploying contracts​

Before you can deploy a contract to the Chain network using web3.js, you must first create an account.

You can create an account by using web3.eth.accounts:

const privateKey = “PRIVATE_KEY”;
const account = web3.eth.accounts.privateKeyToAccount(privateKey);
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PRIVATE_KEY is the private key of the wallet to use when creating the account.

Interacting with smart contracts​

You can use web3.js to interact with a smart contract on Chain by instantiating a Contract object using the ABI and address of a deployed contract:

const abi = [
… // ABI of deployed contract
];

const contractAddress = "CONTRACT_ADDRESS"

const contract = new web3.eth.Contract(abi, contractAddress);

Once you have created a Contract object, you can use it to call desired methods on the smart contract:

async function setValue(value) {
  // write query
  const tx = await contract.methods.set(value).send();
  console.log(tx.transactionHash);
}

async function getValue() {
  // read query
  const value = await contract.methods.get().call();
  console.log(value.toString());
}
info

For more information on deploying contracts on Chain, see Deploying a Smart Contract.