Examples for Module Loader Hooks

Node.js v17 added a new Experimental Feature: Module Loaders(Hooks).

This feature enables you to customize the default module resolution and content loading. So you can import a raw file, remote module (via http/https) (like deno) etc.

Here's some basic examples:

• Loading a txt file and wrapping its content into an ES Module
• Patch an NPM package (like require-in-middle)
• Loading an ES Module from a remote ESM Delivery
• Loading a sass file and compiling it to a css
• …

Something like

import './a.txt';
import repeat from 'repeat-string';
import _ from 'https://cdn.skypack.dev/lodash';
import css from './b.scss';

Requirements

• Node.js >= 17 (Current v17.1.0)
• Using ES Module

Getting Started

This feature needs the --experimental-loader flag with a specific loader.

node --experimental-loader ./lib/index.mjs main.mjs

Output:

[load txt] file content in a.txt: I'm a txt file.

[load npm module] repeat A for 5 times: been patched!!!

[load remote module] lodash.last for [1, 2, 3, 4]: 4

[load scss] css for scss: body {
  font: 100% Helvetica, sans-serif;
  color: #333;
}