How to use require() in ECMAScript modules

ECMAScript modules are now becoming the new way of import/exporting modules in NodeJS ecosystem. This allows you to import and export modules using import statements rather than using require

Example 01

//multiple.js
const multiple = (num1, num2) => {
  return num1 * num2;
};

This can be imported as

import { multiple } from "./multiple.js";

console.log(multiple(10, 50));

Example 02 (Default Export)

Also ECMAScript modules introduces default exports which can be used as

//multiple.js
const multiple = (num1, num2) => {
    return num1 * num2;
};

export default multiple;

Can be imported as

import multiple from "./multiple.js";

console.log(multiple(10, 50));

We can't use ECMAScript modules in a NodeJS app by default. To do this there are two ways.

1. You need to change the file extension of the files from *.js to *.ejs
   

2. You can add "type": "module" in your package.json file
   

{
  "name": "ECMAScript-modules",
  "version": "1.0.0",
  "description": "",
  "type": "module", 
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "",
  "license": "ISC"
}

Most of the modules in NodeJS now supports ECMAScript module imports. But there may be some occasions that we still want to use require.

🔴If you use require in ECMAScript module. it will throw an error.

import crypto from 'crypto'
const fs = require('fs')

Above code will throw following error.

require is not defined in ES module scope, you can use import instead.

Solution 🎉

you can use createRequire to overcome this issue. Following is a sample code how to use it.

import { createRequire } from "module";
const require = createRequire(import.meta.url);

import crypto from 'crypto'
const fs = require('fs')

You can also define this in a separate file and reuse it afterwards.

import { createRequire } from "module";
const require = createRequire(import.meta.url);

export default require;

Then this can be used as

import require from "./cjs-require.";
const crypto = require("crypto");

Hope you've enjoyed reading.

Please comment if you face any problems. I'm happy to help. Also connect with me on twitter

Comments

[Richard Joseph]

For me at least, this is an amazing find, specifically the createRequire( ) call.

Life safer, thank you 🙏🏾