Webpack Virtual Modules

Webpack Virtual Modules is a plugin that allows for dynamical generation of in-memory virtual modules for JavaScript builds created with webpack. When virtual module is created all the parent virtual dirs that lead to the module filename are created too. This plugin supports watch mode meaning any write to a virtual module is seen by webpack as if a real file stored on disk has changed.

Installation

Use NPM or Yarn to install Webpack Virtual Modules as a development dependency:

1# with NPM
2npm install webpack-virtual-modules --save-dev
3
4# with Yarn
5yarn add webpack-virtual-modules --dev

Usage

You can use Webpack Virtual Modules with webpack 5, 4 and 3. The examples below show the usage with webpack 5 or 4. If you want to use our plugin with webpack 3, check out a dedicated doc:

• Webpack Virtual Modules with Webpack 3

Generating static virtual modules

Require the plugin in the webpack configuration file, then create and add virtual modules in the plugins array in the webpack configuration object:

1var VirtualModulesPlugin = require('webpack-virtual-modules');
2
3var virtualModules = new VirtualModulesPlugin({
4  'node_modules/module-foo.js': 'module.exports = { foo: "foo" };',
5  'node_modules/module-bar.js': 'module.exports = { bar: "bar" };'
6});
7
8module.exports = {
9  // ...
10  plugins: [
11    virtualModules
12  ]
13};

You can now import your virtual modules anywhere in the application and use them:

1var moduleFoo = require('module-foo');
2// You can now use moduleFoo
3console.log(moduleFoo.foo);

Generating dynamic virtual modules

You can generate virtual modules dynamically with Webpack Virtual Modules.

Here's an example of dynamic generation of a module. All you need to do is create new virtual modules using the plugin and add them to the plugins array. After that, you need to add a webpack hook. For using hooks, consult webpack compiler hook documentation.

1var webpack = require('webpack');
2var VirtualModulesPlugin = require('webpack-virtual-modules');
3
4// Create an empty set of virtual modules
5const virtualModules = new VirtualModulesPlugin();
6
7var compiler = webpack({
8  // ...
9  plugins: [
10    virtualModules
11  ]
12});
13
14compiler.hooks.compilation.tap('MyPlugin', function(compilation) {
15  virtualModules.writeModule('node_modules/module-foo.js', '');
16});
17
18compiler.watch();

In other module or a Webpack plugin, you can write to the module module-foo whatever you need. After this write, webpack will "see" that module-foo.js has changed and will restart compilation.

1virtualModules.writeModule(
2  'node_modules/module-foo.js',
3  'module.exports = { foo: "foo" };'
4);

More Examples

• Swagger and JSDoc Example with Webpack 5
• Swagger and JSDoc Example with Webpack 4
• Swagger and JSDoc Example with Webpack 3

API Reference

• API Reference

Inspiration

This project is inspired by virtual-module-webpack-plugin.

Contributing

This project uses nari package manager to have reproducible builds without resorting to lockfiles, it uses lockTime field in package.json instead.

To install nari execute: npm i -g nari

And then nari to install the project.

To run project scripts use nari script_name, for example nari test to run unit tests.

License

Copyright © 2017 SysGears (Cyprus) Limited. This source code is licensed under the MIT license.