CommonJS vs ES6 Modules: What's the Difference?

What are the main differences between CommonJS and ES6 modules?

CommonJS is a module system used primarily in Node.js, while ES6 modules are part of the ECMAScript 2015 standard and are used in both browsers and Node.js. CommonJS uses require() to import modules and module.exports to export them, whereas ES6 uses import and export syntax.

Can you give me an example of how to use both?

Sure! In CommonJS, you might have a file called math.js with module.exports = { add: (a, b) => a + b };. In another file, you would use const math = require('./math');. For ES6, in math.js, you would write export const add = (a, b) => a + b; and import it with import { add } from './math.js';.

Are there any performance differences between the two?

Yes, ES6 modules are statically analyzed, which allows for better optimization by the JavaScript engine. CommonJS modules are loaded at runtime, which can lead to slower performance in some cases.

Which one should I use for new projects?

For new projects, it's generally recommended to use ES6 modules due to their modern syntax, better performance, and support in both browsers and Node.js.