webpack-virtual-modules

What is webpack-virtual-modules?

The webpack-virtual-modules package allows developers to inject virtual files into the webpack module system. This can be particularly useful for dynamically generating modules or simulating files during the build process without actually writing them to disk.

What are webpack-virtual-modules's main functionalities?

Dynamic Module Creation

This feature allows developers to create virtual modules that can be used as if they were actual files. This is useful for testing or when certain modules need to be generated on the fly.

const VirtualModulesPlugin = require('webpack-virtual-modules');
const virtualModules = new VirtualModulesPlugin({
  'node_modules/my-virtual-module.js': 'module.exports = "This is a virtual module";'
});

// Webpack configuration
module.exports = {
  plugins: [virtualModules]
};

Simulating File Changes

This feature enables the simulation of file changes during the webpack build process. It can be used to trigger hot module replacement (HMR) or to test how changes in modules affect the build.

const VirtualModulesPlugin = require('webpack-virtual-modules');
const virtualModules = new VirtualModulesPlugin();

virtualModules.writeModule('node_modules/my-virtual-module.js', 'module.exports = "Updated virtual module content";');

Other packages similar to webpack-virtual-modules

memory-fs

Similar to webpack-virtual-modules, memory-fs allows for the creation of a virtual file system. However, it is more general-purpose and can be used outside of webpack for other types of in-memory file storage. It does not integrate directly with webpack's internal mechanisms as seamlessly as webpack-virtual-modules.

README

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:

# with NPM
npm install webpack-virtual-modules --save-dev

# with Yarn
yarn 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:

var VirtualModulesPlugin = require('webpack-virtual-modules');

var virtualModules = new VirtualModulesPlugin({
  'node_modules/module-foo.js': 'module.exports = { foo: "foo" };',
  'node_modules/module-bar.js': 'module.exports = { bar: "bar" };'
});

module.exports = {
  // ...
  plugins: [
    virtualModules
  ]
};

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

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

var webpack = require('webpack');
var VirtualModulesPlugin = require('webpack-virtual-modules');

// Create an empty set of virtual modules
const virtualModules = new VirtualModulesPlugin();

var compiler = webpack({
  // ...
  plugins: [
    virtualModules
  ]
});

compiler.hooks.compilation.tap('MyPlugin', function(compilation) {
  virtualModules.writeModule('node_modules/module-foo.js', '');
});

compiler.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.

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

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.

License

Copyright © 2017 SysGears INC. This source code is licensed under the MIT license.