Metamask: react ethersjs metamask with Custom RPC provider

Here is a step-by-step guide on how to integrate Metamask with React EthersJS and use it as an RPC provider for your Ethereum-based application:

Step 1: Set up MetaMask

Make sure you have MetaMask installed in your browser. If not, download and install it from the [MetaMask official website](

Step 2: Create a Web3 provider instance with Metamask

Create a new file named web3.js in the root of your project directory:


// web3.js
const Web3 = require('web3');
class EthersProvider {
constructor() {
const providerUrl = window.ethereum.selectedAddress;
const networkId = window.ethereum.chainId;
const web3 = new Web3(window.ethereum);
if (providerUrl && networkId) {
web3.providers EthersProvider ({
provider: providerUrl,
chainId: networkId
});
} else {
console.error('MetaMask provider not found');
throw new Error ('MetaMask not installed or selected address not found');
}
}
}
module.exports = EthersProvider;

This code creates an `EthersProviderclass that sets up a Web3 instance with Metamask as the RPC provider. The constructor checks for the MetaMask provider URL and network ID and uses them to create a new Web3 instance.


Step 3: Use EthersProvider in your React app

In your mainApp.jsorindex.jsfile, import theEthersProviderclass and use it as the RPC provider for your Ethereum-based app:

javascript


// App.js
import React from 'react';
import ReactDOM from 'react-dom';
import Web3Provider from './web3.js';
function App() {
return (

{/ Your app content goes here /}

);
}
ReactDOM.render(


{/ Your app content goes here /}
,
document.getElementById('root')
);

Step 4: Use the Web3 instance in your React componentsUse theweb3instance to call Ethereum functions and interact with the blockchain. For example:
javascript
// MyComponent.js
import React, { useState } from 'react';
import web3Provider from './web3.js';
function MyComponent() {
const [accountAddress, setAccountAddress] = useState('0x...');
async function handleGetBalance() {
const balance = await web3Provider.eth.getBalance(accountAddress);
console.log(Account Balance: ${balance});
}
return (

My Component




);
}

This code uses the web3Providerinstance to get the current account address and call thegetBalance` function, which returns the Ethereum account balance.

That’s it!

With these steps, you should now have Metamask set as your RPC provider in React EthersJS. You can use this provider to interact with the blockchain from within your React application.