An universal AMD Loader

Usage no npm install needed!

<script type="module">
  import vscodeLoader from 'https://cdn.skypack.dev/vscode-loader';


VSCode Loader

An universal Asynchronous Module Definition (AMD) Loader developed primarily to load VSCode's sources.

Supported environments

  • IE 11, Edge, Firefox, Chrome, Safari, Opera
  • nodejs
  • electron (renderer & browser processes) In nodejs and electron, when loading a module, if it cannot be found with the AMD rules, it delegates loading them to the native require.


  • Runs factory methods as soon as dependencies are resolved.
  • Contains a CSS loader (vs/css).
  • Contains a natural language strings loader (vs/nls).


  • In a browser environment:
<script type="text/javascript" src="loader.js"></script>
        // ...
    require(['an/amd/module'], function(value) {
        // code is loaded here
  • In a node environment:
var loader = require('loader');
    // ...
loader(['an/amd/module'], function(value) {
    // code is loaded here
  • Supported config options:
  • baseUrl - The prefix that will be aplied to all modules when they are resolved to a location
  • paths - Redirect rules for modules. The redirect rules will affect the module ids themselves
  • config - Per-module configuration
  • catchError - Catch errors when invoking the module factories
  • recordStats - Record statistics
  • urlArgs - The suffix that will be aplied to all modules when they are resolved to a location
  • onError - Callback that will be called when errors are encountered
  • ignoreDuplicateModules - The loader will issue warnings when duplicate modules are encountered. This list will inhibit those warnings if duplicate modules are expected.
  • isBuild - Flag to indicate if current execution is as part of a build.
  • cspNonce - Allows setting a Content Security Policy nonce value on script tags created by the loader.
  • nodeRequire - The main entry point node's require
  • nodeInstrumenter - An optional transformation applied to the source before it is loaded in node's vm

Custom features

  • Recording loading statistics for detailed script loading times:
    recordStats: true
// ...
  • Extracting loading metadata for a bundler:
var loader = require('loader');
    isBuild: true
// ...


To run the tests:

  • code loading in node: npm run test
  • amd spec tests, unit tests & code loading in browser:
    • npm run simpleserver
    • open http://localhost:9999/tests/run-tests.htm

The project uses as a submodule the AMD compliance tests. The goal is to support as many tests without adding eval() or an equivalent. It is also not a goal to support loading CommonJS code:

  • Basic AMD Functionality (basic)
  • The Basic require() Method (require)
  • Anonymous Module Support (anon)
  • CommonJS Compatibility (funcString)
  • CommonJS Compatibility with Named Modules (namedWrap)
  • AMD Loader Plugins (plugins)
  • Dynamic Plugins (pluginsDynamic)
  • Common Config: Packages
  • Common Config: Map
  • Common Config: Module
  • Common Config: Path
  • Common Config: Shim


  • Clone the repository
  • Run git submodule init
  • Run git submodule update
  • Run npm install
  • Compile in the background with npm run watch1 and npm run watch2

Code of Conduct

This project has adopted the Microsoft Open Source Code of Conduct. For more information see the Code of Conduct FAQ or contact opencode@microsoft.com with any additional questions or comments.