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* typos hardhat-deploy-sbs.md * typos hardhat-testing-sbs.md * typos hardhat-testing-sbs.md * typos ethers.md * typos web3.md
134 lines
3.0 KiB
Markdown
134 lines
3.0 KiB
Markdown
---
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title: web3.js
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slug: /tools/web3
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description: Documentation for using web3.js, a JavaScript library for interacting with EVM-compatible blockchains. This page covers installation, setup, connecting to the Base network and interacting with smart contracts.
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keywords:
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[
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web3.js,
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Base,
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Base mainnet,
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Base testnet,
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Base network,
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JavaScript,
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EVM,
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client library,
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blockchain,
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smart contracts,
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Ethereum,
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RPC URL,
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]
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hide_table_of_contents: true
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---
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# web3.js
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[web3.js](https://web3js.org/) is a JavaScript library that allows developers to interact with EVM-compatible blockchain networks.
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You can use web3.js to interact with smart contracts deployed on the Base network.
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---
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## Install
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To install web3.js run the following command:
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```bash
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npm install web3
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```
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## Setup
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Before you can start using web3.js, you need to import it into your project.
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Add the following line of code to the top of your file to import web3.js:
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```javascript
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//web3.js v1
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const Web3 = require('web3');
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//web3.js v4
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const { Web3 } = require('web3');
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```
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## Connecting to Base
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You can connect to Base by instantiating a new web3.js `Web3` object with an RPC URL of the Base network:
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```javascript
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const { Web3 } = require('web3');
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const web3 = new Web3('https://mainnet.base.org');
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```
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:::info
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To alternatively connect to Base Sepolia (testnet), change the above URL from `https://mainnet.base.org` to `https://sepolia.base.org`.
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:::
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## Accessing data
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Once you have created a provider, you can use it to read data from the Base network.
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For example, you can use the `getBlockNumber` method to get the latest block:
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```javascript
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async function getLatestBlock(address) {
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const latestBlock = await web3.eth.getBlockNumber();
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console.log(latestBlock.toString());
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}
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```
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## Deploying contracts
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Before you can deploy a contract to the Base network using web3.js, you must first create an account.
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You can create an account by using `web3.eth.accounts`:
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```javascript
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const privateKey = “PRIVATE_KEY”;
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const account = web3.eth.accounts.privateKeyToAccount(privateKey);
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```
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:::info
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`PRIVATE_KEY` is the private key of the wallet to use when creating the account.
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:::
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## Interacting with smart contracts
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You can use web3.js to interact with a smart contract on Base by instantiating a `Contract` object using the ABI and address of a deployed contract:
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```javascript
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const abi = [
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… // ABI of deployed contract
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];
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const contractAddress = "CONTRACT_ADDRESS"
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const contract = new web3.eth.Contract(abi, contractAddress);
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```
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Once you have created a `Contract` object, you can use it to call desired methods on the smart contract:
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```javascript
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async function setValue(value) {
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// write query
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const tx = await contract.methods.set(value).send();
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console.log(tx.transactionHash);
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}
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async function getValue() {
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// read query
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const value = await contract.methods.get().call();
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console.log(value.toString());
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}
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```
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:::info
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For more information on deploying contracts on Base, see [Deploying a Smart Contract](/tutorials/deploy-with-hardhat).
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:::
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