I am fairly new to Ethereum development, I just tried to follow this tutorial but instead of connection to a public blockchain I am trying to connect to my local blockchain instance through MetaMask which is already installed and the local chain is added to it. However, I am facing an issue at the first line of my code during the "require" part. Here is my code below:

const { ethers } = require("ethers");
const provider = new ethers.providers.Web3Provider(window.ethereum)
async function connectToMetamask(){
   await provider.send("eth_requestAccounts", []);
const signer = provider.getSigner();

const ERC20_ABI = [
   "function getAll() public view returns(uint [] memory)",
   "function get(uint position) public view returns(uint)",
   "function add(uint id, string memory activityName, string memory authorName, string memory activityType) public",
   "function length() public view returns(uint)",

const address = '0xf0c707dafa300d8bd19bbfed42b86469d50b022f';

const contractInstance = new ethers.Contract(address, ERC20_ABI, provider);

const main = async () => {
   const name = await contractInstance.name();
   console.log("name: " , name);


And the error I am facing is below:

Uncaught ReferenceError: require is not defined at code.js:1:20

Can anyone help me with solving this issue? I followed this tutorial step-by-step but doesn't seem to work for me..

Note: I have already written my own contract and deployed it to my local blockchain and that is where I got all these functions and the address from.

1 Answer 1


So after searching for a while through the internet I found what the issue was and how to solve it.

The Issue:

I was trying to run a Node JS code within my browser (which apparently doesn't work, especially if you're using 'require' keyword).

The Solution:

To solve this I had to use browserify.

What browserify does apparently is wrapping your js code into a new js file that can be run within the browser. The usage could be a little confusing, especially for Windows users since after installing browserify in windows the keyword 'browserify' doesn't get recognized in CMD. So here are the steps I did to make my code work:

  • Install browserify by using npm install -g browserify command
  • Navigate to my project's folder with CMD
  • Run this command node .\node_modules\browserify\bin\cmd.js code.js -o bundle.js instead of browserify code.js -o bundle.js because... well Windows. (Note that the "code.js" should be replaced with the name of your js file)
  • Finally included the newly generated bundle.js file instead of my code.js in my html file <script src="bundle.js"></script> and my code finally ran fine.

Hope this answers this question to anyone else after me and they won't have to look for days to find this simple answer.

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