What are the differences between CommonJS and ES6 modules in Node.js?

What are the differences between CommonJS and ES6 modules in Node.js?

CommonJS and ES6 modules are two different module systems in Node.js. CommonJS uses require() to import modules and module.exports to export them, while ES6 modules use import and export syntax. ES6 modules are statically analyzed, which can lead to better optimization by the JavaScript engine.

Can you give me an example of how to use both in a Node.js project?

Sure! For CommonJS, you would do something like this:

// math.js (CommonJS)
const add = (a, b) => a + b;
module.exports = add;

And to use it:

// app.js
const add = require('./math');
console.log(add(2, 3)); // 5

For ES6:

// math.js (ES6)
export const add = (a, b) => a + b;

And to use it:

// app.js
import { add } from './math.js';
console.log(add(2, 3)); // 5

Are there any performance differences between the two?

Yes, ES6 modules can be more performant due to their static structure, allowing for better tree-shaking and optimization. However, the actual performance can depend on the specific use case and how the modules are structured.

Which one should I use for new projects?

For new projects, it's generally recommended to use ES6 modules as they are the standard moving forward and offer better features like static analysis and improved syntax.