JavaScript Module Loader

The project provide another runtime module loader isolated from the default module loaders (global require, import() mechanism), and is easy for instrumenting the code. It is suitable for testing multiple JavaScript modules in an isolated environment.

How to Use

General Usage Patterns

function loadModule(modulePath: string, options?: LoadOptions): any;
function loadModuleAsync(modulePath: string, options?: LoadOptions): Promise<any>;

The second format is to load the module asynchronously (corresponding to import()).

Parameters are explained as follows:

Parameter	Explanation
modulePath	Absolute (or relative path to the working directory) to a Node.js module
options	Additional options (detailed below)

Supported options:

Option name	Type	Description
instrumentFunc	Function or null	function for instrumentation, accepting 2 arguments (code string and file name)
subpath	string	the subpath of a module to load (e.g., helpers in require('yargs/helpers'))
globalThis	object	the mocked globalThis for executing the initialization code in the loading process
returnSourceFiles	boolean	whether to return all included source files
cache	object	the cache object in loading the module
patchExportDefault	object	whether to return the default export separately

Example

Suppose that yargs module is installed at /home/test/yargs. Now you want to load yargs via subpath import, you can use loadNodeJSModule as follows:

const loadNodeJSModule = require('js-module-loader');
let mod = loadNodeJSModule('/home/test/yargs', true, {subPath: 'helpers'});
let hideBin = mod.hideBin;

This is equivalent to the code const { hideBin } = require('yargs/helpers') (CommonJS) or import { hideBin } from 'yargs/helpers' (ESM).

Contact

For any questions and suggestions, please contact me via mail AT dezhen DOT org.