esm

What is esm?

The esm npm package is a lightweight module loader that allows developers to use ES6 modules in Node.js. It enables the use of import and export syntax for working with modules, which is more standardized and often considered cleaner than the traditional CommonJS require syntax.

What are esm's main functionalities?

Import ES6 Modules

Allows the use of ES6 import syntax in Node.js by requiring the esm module and then using it to load other ES6 modules.

require = require('esm')(module)
const { myFunction } = require('./myModule.mjs')

Export ES6 Modules

Enables developers to define modules using ES6 export syntax, which can then be imported by other modules.

// In myModule.mjs
export const myFunction = () => { console.log('Hello ESM!'); }

Dynamic Import

Supports dynamic import() syntax for loading modules asynchronously, which can be useful for code splitting or on-demand loading.

require = require('esm')(module)
const myModule = require('./myModule.mjs')
myModule.then(module => { module.myFunction() })

Other packages similar to esm

@babel/register

This package allows you to transpile your ES6+ code on the fly by hooking into Node's require. It is more feature-rich than esm, offering a wide range of plugins to transform your code, but it may be heavier and slower for simple use cases.

ts-node

While ts-node is primarily for running TypeScript in Node.js without pre-compiling, it also supports ES6+ features. It is similar to esm in that it allows for the use of modern module syntax, but it is specifically tailored for TypeScript.

esbuild-register

This package uses esbuild to transpile code when requiring modules. It's similar to esm in that it allows you to use newer syntax, but it also includes TypeScript support and is focused on speed, leveraging the fast esbuild bundler.

README

esm