mini-extract-plugin

mini-extract-plugin

Generalized and hookable mini-css-extract-plugin. Extract any format, process it your way.

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🪑 Table of Content

• 🧰 Features
• 👶 Install
• 🚀 Usage
• 🔮 Background
• 🤖 API
• ⏳ Changelog
• 🛠 Developing
• 🏗 Roadmap
• 🤝 Contributing
• 🧙 Contributors
• ⭐ Show your support
• 🐙 Community
• 🔗 Related Projects
• 👨‍🔧 Maintainers
• 📝 License

🧰 Features

• Exposes 18 hooks that enable you to:

  • Override how the modules are parsed when passed to the loader
  • Override how the modules are merged into a common file
  • Override what content is returned instead of the content was extracted.
  • Define if and how the modules should should be split
  • Hook into the compiler / compilation.
  • Extend initialization

• Based on mini-css-extract-plugin v0.9.0, this package recycles the same logic, but allows you override the format-specific logic and more.

• See how the original mini-css-extract-plugin has been reimplemented using this package.

👶 Install

npm install mini-extract-plugin

🚀 Usage

Creating new MiniExtractPlugin classes

For a minimal setup, just import the plugin and give it a unique type name by which the plugin will be known. The instances of the created class can be used in Webpack.

// Default import is a class factory
import mep from 'mini-extract-plugin';

// Minimal config
const MyMiniExtractPlugin =  mep({
  type: 'my-custom-type'
});

// Create instance to be used in the config.
// Class constructor optionally accepts an options object
const myMEP = new MyMiniExtractPlugin({
  ...
});

// webpack config
const config = {
  ...
  module: {
    rules: [
      {
        // We want all encountered files named "*.some.json"
        // to be extracted into separate files.
        //
        // The files could be e.g. i18n files, or some config
        // files that are defined in multiple places but we want
        // a single file that combines all matched files.
        resourceQuery: /\.some\.json$/,
        use: [
          // Register the plugin as a loader
          // `asLoader` is an object so we have to use it in the
          // `use` array
          myMEP.asLoader,
        ],
        ...
      }
    ],
  },
  plugins: [
    // Register the plugin as a plugin.
    myMEP,
    ...
  ]
}

However, this example above is not terribly useful since we haven't specified any hooks. That means, for example, that found JSONs will be concatenated into as single file as strings (e.g. "{}" + "{}"), but that won't yield a valid JSON. So to make the new plugin class to work properly, we need to speficy more than just the type.

import mep from 'mini-extract-plugin';

const MyMiniExtractPlugin = mep({
  type: 'my-custom-type',
  displayName: `My Super Awesome Extract Plugin`,
  hooks: [
    // Tap sync function `compilationHookFn` into `compilation`
    // hook.
    // Maybe we want to tap into the Webpack's Compilation
    // instance
    {
      name: 'compilation',
      type: 'tap',
      hooks: [compilationHookFn],
    },
    // Tap sync function `mergeHookFn` into `merge` hook.
    // Here we will override how the modules should be
    // concatenated (instead of string concat, we join JSONs
    // as objects)
    { name: 'merge', type: 'tap', hooks: [mergeHookFn] },
  ],
});

// Create instance to be used in the config.
const myMEP = new MyMiniExtractPlugin();
...

This is better! We have specified how the modules should be merged and so when we use this plugin in the Webpack now, the end result will be a proper JSON.

This way, you can override only the parts of the process that needs to be modified. You can also tap multiple functions into any single hook. And where available, you can also tap asynchronously. Some hooks are "waterfall", meaning that result from one function is passed to another. Other are regular hooks where the tapped functions don't interact. See tapable for details on how hooks work.

For details on what hooks are available, their signatures, whether they're sync or async, etc, see Hooks.

You may have noticed that we've also specified a displayName property. Additional options allow you to:

• override what classes should be used for modules, dependencies, and other Webpack entities (useful if you want to pass custom data along with the modules).
• override what options can be passed to the class constructor when creating a plugin instance (by default, mini-css-extract-plugin options are used)
• override the name of the created class, and how it is displayed.

See full description of the class options here.

Examples

• mini-css-extract-plugin fixture - Test re-implementation of mini-css-extract-plugin
• mini-i18n-extract-plugin - Extract i18n files (JSON / YAML) and split the files by entrypoints and language locales.

Subclassing

Class factory

Here's an example how MiniExtractPlugin can be subclassed taken from the mini-css-extract-plugin replimenetation

import miniExtractPluginFactory, { types } from 'mini-extract-plugin';
import Module from './module';
import ModuleFactory from './module-factory';
import Dependency from './dependency';
import DependencyTemplate from './dependency-template';
import hooks from './hooks';
import { type, typeReadable } from './config';

const MiniExtractPluginClass = miniExtractPluginFactory<{
  dependencyClass: types.DependencyClass<Dependency>;
  moduleClass: types.ModuleClass<Module>;
  moduleFactoryClass: typeof ModuleFactory;
}>({
  type,
  displayName: `My Mini ${typeReadable} Extract Plugin`,
  moduleFactoryClass: ModuleFactory,
  dependencyClass: Dependency,
  dependencyTemplateClass: DependencyTemplate,
  hooks: [
    { name: 'compilation', type: 'tap', hooks: [hooks.compilation!] },
    { name: 'merge', type: 'tap', hooks: [hooks.merge!] },
  ],
});

export default MiniExtractPluginClass;

The factory function is passed:

• identifiers type and optional displayName.
• custom subclasses dependencyClass, moduleClass, and dependencyTemplateClass.
• compilation and merge hooks.

Factory function was also given an object as a type parameter. This object specifies which types should be used for classes and options, and enable type inferrence for subclasses with custom classes and options.

Full list of type options with their defaults:

const MyMiniExtractPlugin = miniExtractPluginFactory<{
  // These reflect the types of the classes that we pass to the
  // class factory as options.
  dependencyClass?: DependencyClass;
  dependencyTemplateClass?: DependencyTemplateClass;
  moduleClass?: ModuleClass;
  moduleFactoryClass?: ModuleFactoryClass;
  // Type of the options object passed to constructor on instantiations.
  constructorOptions?: { [key: string]: any };
} = {}
>(...)

Options classes

Classes that can be passed to the factory function can be found at the root of the export. Subclassing is as simple as:

import {
  Dependency,
  DependencyTemplate,
  Module,
  ModuleFactory,
} from 'mini-extract-plugin';

class DependencySubclass extends Dependency {}
class DependencyTemplateSubclass extends DependencyTemplate {}
class ModuleSubclass extends Module {}
class ModuleFactorySubclass extends ModuleFactory {}

If you use TypeScript and want to override the types these subclass use in methods / constructor, you can pass type arguments. This is useful e.g. if your subclass adds properties, and you want TypeScript to recognize those properties.

All type parameters that can be passed to classes + their defaults:

import {
  subclassDependency,
  subclassDependencyTemplate,
  subclassModule,
  subclassModuleFactory,
} from 'mini-extract-plugin';

class DependencySubclass extends Dependency<{
  // Options object passed to the Dependency constructor
  dependencyOptions: DependencyOptions;
}> {}

// subclassDependencyTemplate has no type parameters
class DependencyTemplateSubclass extends DependencyTemplate {}

class ModuleSubclass extends Module<{
  // Dependency class whose instance is passed to the Module
  // constructor
  dependency: Dependency;
}> {}

class ModuleFactorySubclass extends ModuleFactory<{
  // Dependency class that is passed to ModuleFactory.create
  dependency: Dependency;
  // Module class whose instance is created in ModuleFactory.create
  // from Dependency
  module: Module;
}> {}

Subclassing helpers

If you need to subclass any of the above but don't need to override the behaviour, you can use helper subclassing functions.

Each of them accepts options

import {
  subclassDependency,
  subclassDependencyTemplate,
  subclassModule,
  subclassModuleFactory,
} from 'mini-extract-plugin';

// `type` is the same `type` argument passed to class factory
const DependencySubclass = subclassDependency({ type: 'custom-plugin' });
const DependencyTemplateSubclass = subclassDependencyTemplate({
  type: 'custom-plugin',
});
const ModuleSubclass = subclassModule({ type: 'custom-plugin' });
const ModuleFactorySubclass = subclassModuleFactory({
  type: 'custom-plugin',
  moduleClass: MyCustomModule, // Optionally define module class
});

If you use TypeScript and want to override the classes these subclass use, you can pass type arguments. The type arguments passed to subclass helpers are same as to the classes.

Given the example from above, if you want to module type created by ModuleFactorySubclass to match MyCustomModule, you can do following:

const ModuleFactorySubclass = subclassModuleFactory<{
    module: Module;
  }({
  type: 'custom-plugin',
  moduleClass: MyCustomModule,
});

All type parameters that can be passed to helper functions + their defaults:

import {
  subclassDependency,
  subclassDependencyTemplate,
  subclassModule,
  subclassModuleFactory,
} from 'mini-extract-plugin';

const DependencySubclass = subclassDependency<{
  // Options object passed to the Dependency constructor
  dependencyOptions: DependencyOptions;
}>(...);

// subclassDependencyTemplate has no type parameters
const DependencyTemplateSubclass = subclassDependencyTemplate(...);

const ModuleSubclass = subclassModule<{
  // Dependency class whose instance is passed to the Module
  // constructor
  dependency: Dependency;
}>(...);

const ModuleFactorySubclass = subclassModuleFactory<{
  // Dependency class that is passed to ModuleFactory.create
  dependency: Dependency;
  // Module class whose instance is created in ModuleFactory.create
  // from Dependency
  module: Module;
}>(...);

See how classes are extended in the re-implementation of mini-css-extract-plugin.

Helpers

The package also exposes a util export, which contains utility modules used for working with the hooks or objects passed to hook functions:

• util.module includes helper functions for working with modules.
• util.subclass includes helper functions for subclassing the classes that can be passed to the class factory. Use these functions if you need a subclass but don't care about implementation.

Typing

This project is written in TypeScript and the typings are included under the types import.

• types, the root, includes interfaces related to subclassing (MiniExtractPlugin, class factory options, etc.)
• types.context includes interfaces for the contexts passed to tapped functions
• types.hook includes types related to Hooks (Hook overrides, types of recognized hooks, etc.)
• types.webpack is a shim for Webpack, it includes types that either are not exposed in Webpack v4, or which have modified interfaces in the extraction process, so the provided types reflect the actual interface.
• types.util includes helper types which may or may not be useful when working with the hooks.

What you will most likely want is to have the hook functions types inferred. You can use the types.hook.Taps interface, which is an object of { [hookName]: hookFunction }. If you want to define only some hooks, use types.hook.PartialTaps.

Both types accept MiniExtractPlugin interface as a type parameter. Use it to have correct types for arguments and return functions. The passed interface affects the inferred types of context objects, classes passed to MiniExtractPlugin (module, dependency, moduleFactory, ...).

import { types } from 'mini-extract-plugin';

import { IMyMiniExtractPlugin } from './types'

const hooks: types.hook.PartialTaps<IMyMiniExtractPlugin> = {
  // Arguments of `dependency` are inferred thanks to
  // `PartialTaps`
  dependency: (context, {exports: exported}) => {
    const { childCompilation, classOptions } = context;
    ...
};

Debugging

This project uses debug. To show debug logs, activate debug for mini-extract-plugin.

CLI example:

DEBUG=mini-extract-plugin node path/to/my/mini-extract-plugin-project

🔮 Background

mini-css-extract-plugin is great because it allows you to have modularized definitions, which are then merged or split as necessary for you during the build.

This is important for bundle optimization, but also for maintainability, as you can keep the information where it makes sense, without making a tradeoff in logistics.

When working with Vue, I was hoping to manage other auxiliary file types (i18n and documentation, to be specific) in a similar manner - modularized definition but processed and emitted as separate files during build.

There's (understandably) not as much support for other file formats as there is for CSS. But since other formats could benefit from same action,generalizing the process was in order (and thus encouraging modularized approach for more formats).

🤖 API

TypeDoc documentation can be found here.

Options

interface ClassOptions {
  type: string;
  pluginName?: string;
  displayName?: string;
  className?: string;
  moduleType?: string;
  pluginOptionsSchema?: any;
  loaderOptionsSchema?: any;
  dependencyTemplateClass?: DependencyTemplateClass;
  dependencyClass?: DependencyClass;
  moduleFactoryClass?: ModuleFactoryClass;
  moduleClass?: ModuleClass;
  hooks?: Overrides;
}

The class factory accepts an object with following options:

• type - (Required) Namespace used by this class to distinguish it, its instances, and webpack resources (e.g. modules and dependencies) from other MiniExtractPlugin classes.

  • E.g. MiniCssExtractPlugin uses css, MiniI18nExtractPlugin uses i18n

• pluginName - Name of plugin used in identifiers. Prefer package-like (kebab-case) format.

  • Default: mini-${type}-extract-plugin.

• displayName - String to be used when printing the class in logging messages or similar.

  • Default: Mini ${type} Extract Plugin where type is capitalized.

• className - Name of the plugin class that is shown when calling either class.toString() or class.name.

  • Default: Mini${type}ExtractPlugin where type is capitalized.

• moduleType - Identifier used to find modules processed by the class.

  • Default: ${type}/mini-extract.

• pluginOptionsSchema - JSON schema used to validate options passed to constructor and used in loader methods.

  • Default: MiniCssExtractPlugin's plugin options schema

• loaderOptionsSchema - JSON schema used to validate options passed to constructor and used in plugin methods.

  • Default: MiniCssExtractPlugin's plugin options schema

• dependencyTemplateClass - Class that implements Webpack's DependencyTemplate interface.

  • The instance of dependencyTemplateClass must have a method apply.
  • Default: Default is empty implementation. (see source file).

• dependencyClass - Class that implements Webpack's Dependency interface.

  • Dependencies are used among other to pass data to Modules. Data passed to Dependency constructor can be overriden in dependency hook.
  • If providing ypur own Dependency class, be sure to subclass the default implementation to ensure the plugin works as expected. See the re-implementation of MiniCssExtractPlugin for an example of how the Dependency class can be extended.
  • Default: Default implementation ensures the MiniExtractPlugin works correctly. It stores information on MiniExtractPlugin type, identifier, context, and content (see source file).

• moduleFactoryClass - Class that implements Webpack's Module Factory interface.

  • The instance of moduleFactoryClass must have a method create that is called with data and callback and must call the callback with either an error as first argument or Module instance as second argument. The data contains an array-wrapped dependency of class dependencyClass.
  • Default: Default implementation passed the dependency to Module constructor (see source file). If moduleClass is specified, the created Module will be of class moduleClass. Otherwise Webpack's Module class is used.

• moduleClass - Class that implements Webpack's Module interface.

  • This class used only with the default moduleFactoryClass implementation. If you specify moduleFactoryClass, this option is ignored.
  • Module constructor accepts a dependency of class dependencyClass.
  • If providing your own Module class, be sure to subclass the default implementation to ensure the plugin works as expected. See the re-implementation of MiniCssExtractPlugin for an example of how the Module class can be extended.
  • Default: Default implementation ensures the MiniExtractPlugin works correctly, and it updates identifiers and hashes (see source file).

• hooks - Array of objects specifying which Tapable hooks should be tapped with what functions, and how the hook should behave (sync/async). See Hooks for the list of available hooks.

  • Each object is expected to implement the hook Override interface:

    Property	Description	Type	Default
    name	Name of the hook to be tapped.	string	-
    type	How should be the functions applied to the hook. These are the methods defined by tapable Options: 'tap' | 'tapAsync' | 'tapPromise' | 'intercept' Note: tapAsync and tapPromise are available only for async hooks. See tapable documentation for details.	string	-
    hooks	Array of functions that should be applied to the hook. Functions are expected to conform to the hook signature they are tapping to. For details on using sync- / promise- / callback-style functions, see tapable documentation. See how the hooks are defined in MiniCssExtractPlugin re-implementation.	Function[]	[]

Hooks order

Hooks are called in following order:

• Plugin initialization
  • initialize
• Plugin.apply is called
  • compiler
  • compilation
• Modules passed to loader: Loader.pitch is called and modules are processed to dependencies
  • pitch
  • childCompiler
  • source
  • childCompilation
  • dependency
  • extracted
• If non-entrypoint chunks are emitted: Render and merge chunks' modules
  • beforeRenderChunk
  • renderChunk
  • afterRenderChunk
  • If using default renderChunk, specify module merging
    • beforeMerge
    • merge
    • afterMerge
• Render and merge entrypoint's modules
  • beforeRenderMain
  • renderMain
  • afterRenderMain
  • If using default renderMain, specify module merging
    • beforeMerge
    • merge
    • afterMerge

Hooks

The available hooks in alphabetical order are (see source file):

afterMerge

• Signature: (RenderContext, Source) => void

• Hook: SyncHook

• Hook called after Modules were merged into a single Source that will be emitted into a file.

  Use this hook if you want to modify the resulting Source without overriding the merging process itself, or if you want to trigger some behaviour after the merge step has finished.

• Default: No behaviour.

  Argument	Description
  RenderContext	Context available on Compilation's renderManifest hook. See RenderContext for details.
  Source	Instance of Webpack's Source (value returned by merge).

afterRenderChunk

• Signature: (RenderContext, RenderManifestEntry[]) => void

• Hook: SyncHook

• Hook called after the list of RenderManifestEntries has been prepared for the generation of chunk (non-entrypoint) files.

  Use this hook if you want to modify the resulting list of RenderManifestEntries without overriding the renderChunk process itself, or if you want to trigger some behaviour after the renderChunk step has finished.

• Default: No behaviour.

  Argument	Description
  RenderContext	Context available on Compilation's renderManifest hook. See RenderContext for details.
  RenderManifestEntry	List of Webpack's RenderManifestEntry objects that will be used to render and create output files. (values processed by renderChunk).

afterRenderMain

• Signature: (RenderContext, RenderManifestEntry[]) => void

• Hook: SyncHook

• Hook called after the list of RenderManifestEntries has been prepared for the generation of main (entry) files.

  Use this hook if you want to modify the resulting list of RenderManifestEntries without overriding the renderMain process itself, or if you want to trigger some behaviour after the renderMain step has finished.

• Default: No behaviour.

  Argument	Description
  RenderContext	Context available on Compilation's renderManifest hook. See RenderContext for details.
  RenderManifestEntry	List of Webpack's RenderManifestEntry objects that will be used to render and create output files. (values processed by renderMain).

beforeMerge

• Signature: (RenderContext, Module[]) => Module[]

• Hook: SyncWaterfallHook

• Hook called when merging multiple Modules into a single Source that will be emitted into a file.

  Use this hook if you want to modify the list of modules without overriding the merging process itself.

• Default: No modifications done.

Argument	Description
RenderContext	Context available on Compilation's renderManifest hook. See RenderContext for details.
Modules	List of Options.moduleClass modules.

Returns	Description
Modules	Processed list of Options.moduleClass modules.

beforeRenderChunk

• Signature: (RenderContext, Module[]) => Module[] | Module[][]

• Hook: SyncWaterfallHook

• Hook called when Webpack is generating a chunk (non-entrypoint file) from the given set of modules.

  Use this hook if you want to modify the list of modules or if you want to split the list of modules into multiple chunks without overriding the rendering process itself.

  This hook is called only if the extracted Dependencies from dependency hook were split into chunks by Webpack.

• Default: No modifications done.

  Argument	Description
  RenderContext	Context available on Compilation's renderManifest hook. See RenderContext for details.
  Modules	List of Options.moduleClass modules.

  Returns	Description
  ModulesGroups	List or list of lists of Options.moduleClass modules. If a list of lists is returned, these are interpreted as module groups. Each module group will emit separate chunk file.

beforeRenderMain

• Signature: (RenderContext, Module[]) => Module[] | Module[][]

• Hook: SyncWaterfallHook

• Hook called when Webpack is generating a main (entry) file from the given set of modules.

  Use this hook if you want to modify the list of modules or if you want to split the list of modules into multiple groups without overriding the rendering process itself.

• Default: No modifications done.

  Argument	Description
  RenderContext	Context available on Compilation's renderManifest hook. See RenderContext for details.
  Modules	List of Options.moduleClass modules.

  Returns	Description
  ModulesGroups	List or list of lists of Options.moduleClass modules. If a list of lists is returned, these are interpreted as module groups. Each module group will emit separate file.

childCompilation

• Signature: (PitchCompilationContext) => void

• Hook: SyncHook

• Hook called when the compilation of child Compiler is run.

  Use this hook if you need to modify the child Compiler's Compilation or if you want to access child Compiler's Compilation's hooks yourself.

• Default: No behaviour.

  Argument	Description
  PitchCompilationContext	Context available in loader's pitch function on child Compiler's thisCompilation hook. See PitchCompilationContext for details.

childCompiler

• Signature: (PitchCompilerContext) => void

• Hook: AsyncParallelHook

• Hook called after a child Compiler was set up in loader's pitch method. Child Compiler is used to evaluate the modules passed to the loader, and the resulting content will be extracted.

  Use this hook if you need to modify the child Compiler before other hooks are tapped, or if you want to access child Compiler's hooks yourself.

• Default: No behaviour.

  Argument	Description
  PitchCompilerContext	Context available in loader's pitch function on creation of child Compiler instance. See PitchCompilerContext for details.

compiler

• Signature: (CompilerContext) => void

• Hook: SyncHook

• Hook called at the beginning of plugin's apply method. Use if you need to access Compiler hooks or if you need to set things up at the beginning of the process.

• Default: No behaviour.

  Argument	Description
  CompilerContext	Context available in Plugin's apply method. See CompilerContext for details.

compilation

• Signature: (CompilationContext) => void

• Hook: SyncHook

• Hook called at the beginning of Compiler's thisCompilation hook. Use if you need to access Compilation hooks.

• Default: No behaviour.

  Argument	Description
  RenderContext	Context available on Compiler's thisCompilation hook. See CompilationContext for details.

dependency

• Signature: (PitchCompilationContext, LoaderModuleContext) => DependencyOptions[]

• Hook: SyncWaterfallHook

• Process the data that was obtained from evaluating the source code of the Module that was passed to loader's pitch method.

  The data should be processed to objects that can be passed to dependencyClass, which will be used by Webpack to create the extracted files.

  Use this hook if you need to modify the data from Module before it is passed to the dependencyClass, or if need to split/merge the evaluated data.

• Default: MiniCssExtractPlugins-derived behaviour. Exported data is interpreted as an arrray of [ID, content] (see source file).

Argument	Description
PitchCompilationContext	Context available in loader's pitch function on child Compiler's thisCompilation hook. See PitchCompilationContext for details.
LoaderModuleContext	Data generated by evaluating the source code of the Module that triggered the MiniExtractPlugin's loader. See LoaderModuleContext.

Returns	Description
DependencyOptions	List of options objects to be passed to the dependencyClass to create Webpack's Dependencies.

extracted

• Signature: (PitchCompilationContext, string) => string

• Hook: SyncWaterfallHook

• Modify the source string of the module from which content has been extracted before it is passed to Webpack.

  Use this hook if you need to modify the string so it can conforms to a loader / parser that it will be passed to next.

• Default: Inserts comment // extracted by plugin-name plus HMR compat.

Argument	Description
PitchCompilationContext	Context available in loader's pitch function on child Compiler's thisCompilation hook. See PitchCompilationContext for details.
remainingSource	String that will be returned to Webpack as the source of the module from which data has been extracted.

Returns	Description
string	String that will be returned to Webpack as the source of the module from which data has been extracted.

initialize

• Signature: (MiniExtractPlugin, object) => void

• Hook: SyncHook

• Modify the MiniExtractPlugin instance during initialization (called from constructor). This hook is called after other initialization logic is done.

  Use this hook if you need to extend the class with custom methods / properties, or to set default options values.

• Default: No behaviour.

Argument	Description
instance	MiniExtractPlugin instance that is being constructed.
instanceOptions	Options object with which the instance is being constructed.

merge

• Signature: (RenderContext, Module[]) => Source

• Hook: SyncWaterfallHook

• Hook called when merging multiple Modules into a single Source that will be emitted into a file.

  Use this hook if you want to override how Modules are merged.

• Default: Join contents with newline (\n).

Argument	Description
RenderContext	Context available on Compilation's renderManifest hook. See RenderContext for details.
Modules	List of Options.moduleClass modules (values processed by beforeMerge).

Returns	Description
Source	Instance of Webpack's Source with content from the modules.

pitch

• Signature: (PitchContext) => void

• Hook: AsyncParallelHook

• Hook called at the beginning of loader's pitch method. Use if you need to set up the loader environment.

• Default: No behaviour.

Argument	Description
PitchContext	Context available in loader's pitch function. See PitchContext for details.

renderChunk

• Signature: (RenderContext, Module[][]) => RenderManifestEntry

• Hook: SyncWaterfallHook

• Hook called when Webpack is generating a chunk (non-entrypoint file) from the given set of module groups. Each module group should yield a separate file. The hook should return a list of RenderManifestEntry objects which specify the metadata of the to-be-generated file(s).

  Use this hook if you want to override how the module groups are rendered and processed for the chunk generation.

  This hook is called only if the extracted Dependencies from dependency hook were split into chunks by Webpack.

  • Default: MiniCssExtractPlugins-derived behaviour (see source file).

  Argument	Description
  RenderContext	Context available on Compilation's renderManifest hook. See RenderContext for details.
  moduleGroups	List of lists of Options.moduleClass modules (values processed by beforeRenderChunk).

  Returns	Description
  RenderManifestEntry	List of Webpack's RenderManifestEntry objects that will be used to render and create output chunk files.

renderMain

• Signature: (RenderContext, Module[][]) => RenderManifestEntry

• Hook: SyncWaterfallHook

• Hook called when Webpack is generating a main (entrypoint) file from the given set of module groups. Each module group should yield a separate file. The hook should return a list of RenderManifestEntry objects which specify the metadata of the to-be-generated file(s).

  Use this hook if you want to override how the module groups are rendered and processed for the entry file generation.

  • Default: MiniCssExtractPlugins-derived behaviour (see source file).

  Argument	Description
  RenderContext	Context available on Compilation's renderManifest hook. See RenderContext for details.
  moduleGroups	List of lists of Options.moduleClass modules (values processed by beforeRenderMain).

  Returns	Description
  RenderManifestEntry	List of Webpack's RenderManifestEntry objects that will be used to render and create output files.

source

• Signature: (PitchCompilationContext) => string

• Hook: AsyncSeriesWaterfallHook

• Get source code from a Module that was passed to loader's pitch method. Use this hook if you need to modify the source code before it is evaluated.

• Default: No modifications done.

  Argument	Description
  PitchCompilationContext	Context available in loader's pitch function on child Compiler's thisCompilation hook. See PitchCompilationContext for details.

  Returns	Description
  ModuleSourceCode	String representation of the Module's content that was intercepted by the loader.

Contexts

Hooks can be tapped to modify the extraction process at different stages. Therefore, also the information available is different. That's why different hooks expose different "contexts", or objects with contextual information available at the point in time of the call.

If you're using TypeScript, the type of the MiniExtractPlugin that is accessible from the context objects (together with its options and classOptions) can be overriden by passing your custom subclass as the first type parameter to the context type.

import { types } from 'mini-extract-plugin';
let context: types.context.CompilationContext<MyMiniExtractPlugin>;

Here is the list of used contexts (see source file):

CompilerContext

Property	Description	Type
plugin	Instance of MiniExtractPlugin where the process occurs	MiniExtractPlugin
classOptions	Class options used to create the MiniExtractPlugin class that was used to create this instance. Shorthand for plugin.classOptions. See Options.	Options
options	Options passed to the MiniExtractPlugin instance. Shorthand for plugin.options. Options object is defined by the pluginOptionsSchema and loaderOptionsSchema class option.	object
compiler	Webpack's Compiler instance exposed to the plugin's apply method.	Compiler

CompilationContext

Same as CompilerContext plus following:

Property	Description	Type
compilation	Webpack's Compilation instance exposed by tapping to Compiler's thisCompilation hook.	Compilation

RenderContext

Same as CompilationContext plus following:

Property	Description	Type
renderEntries	List of Webpack's RenderManifestEntry objects to be rendered, exposed by tapping to MainTemplate's renderManifest hook.	RenderManifestEntry
renderOptions	Webpack's RenderManifestOptions exposed by tapping to MainTemplate's renderManifest hook.	RenderManifestOptions

Example of RenderManifestOptions object

{
  chunk: Chunk {
    id: 'entry2',
    ids: [Array],
    debugId: 1047,
    name: 'entry2',
    preventIntegration: false,
    entryModule: [NormalModule],
    _modules: [SortableSet [Set]],
    filenameTemplate: undefined,
    _groups: [SortableSet [Set]],
    files: [],
    rendered: false,
    hash: '61a4b63e502b1ca58699200b35ff1691',
    contentHash: [Object: null prototype],
    renderedHash: '61a4b63e502b1ca58699',
    chunkReason: undefined,
    extraAsync: false,
    removedModules: undefined
  },
  hash: '9d88bf494be3f1082cdb',
  fullHash: '9d88bf494be3f1082cdbb4388c176e06',
  outputOptions: {
    path: '/Users/path/to/project/dist',
    filename: '[name].js',
    chunkFilename: '[name].js',
    webassemblyModuleFilename: '[modulehash].module.wasm',
    library: '',
    hotUpdateFunction: 'webpackHotUpdate',
    jsonpFunction: 'webpackJsonp',
    chunkCallbackName: 'webpackChunk',
    globalObject: 'window',
    devtoolNamespace: '',
    libraryTarget: 'var',
    pathinfo: true,
    sourceMapFilename: '[file].map[query]',
    hotUpdateChunkFilename: '[id].[hash].hot-update.js',
    hotUpdateMainFilename: '[hash].hot-update.json',
    crossOriginLoading: false,
    jsonpScriptType: false,
    chunkLoadTimeout: 120000,
    hashFunction: 'md4',
    hashDigest: 'hex',
    hashDigestLength: 20,
    devtoolLineToLine: false,
    strictModuleExceptionHandling: false
  },
  moduleTemplates: { javascript: [ModuleTemplate], webassembly: [ModuleTemplate] },
  dependencyTemplates: Map(34) {
    'hash' => '',
    [Function: CssDependency] => CssDependencyTemplate {},
    [Function] => ConstDependencyTemplate {},
    ...
  }
}

PitchContext

Property	Description	Type
plugin	Instance of MiniExtractPlugin where the process occurs	MiniExtractPlugin
classOptions	Class options used to create the MiniExtractPlugin class that was used to create this instance. Shorthand for plugin.classOptions. See Options.	Options
options	Options passed to the MiniExtractPlugin instance. Shorthand for plugin.options. Options object is defined by the pluginOptionsSchema and loaderOptionsSchema class option.	object
loaderContext	Webpack's Loader Context.	LoaderContext
remainingRequest	Request part ahead of the pitch. A string passed to pitch as the first argument. See Webpack's Loader API.	string
precedingRequest	Request part past the pitch. A string passed to pitch as the second argument. See Webpack's Loader API.	string
data	Data object to passed to pitch as the third argument. See Webpack's Loader API.	object

PitchCompilerContext

Same as PitchContext plus the following:

Property	Description	Type
childCompiler	Child instance of Webpack's Compiler used to render the extracted modules.	Compiler

PitchCompilationContext

Same as PitchCompilerContext plus the following:

Property	Description	Type
childCompilation	Webpack's Compilation instance exposed by tapping to child Compiler's thisCompilation hook.	Compilation

LoaderModuleContext

Data generated by evaluating the source code of the Module that triggered the MiniExtractPlugin's loader. The data is used to create Dependencies that will be used to emit files with extracted content.

Property	Description	Type
source	String representation of the source code (value returned by source hook).	string
locals	Local variables from the evaluated source code.	any
exports	Exported variables from the evaluated source code.	any

⏳ Changelog

This projects follows semantic versioning. The changelog can be found here.

🛠 Developing

If you want to contribute to the project or forked it, this guide will get you up and going.

🏗 Roadmap

There is no explicit roadmap for this project. However, if you have ideas how it could be improved, please be sure to share it with us by opening an issue.

🤝 Contributing

Contributions, issues and feature requests are welcome! Thank you ❤️

Feel free to dive in! See current issues, open an issue, or submit PRs.

How to report bugs, feature requests, and how to contribute and what conventions we use is all described in the contributing guide.

When contributing we follow the Contributor Covenant. See our Code of Conduct.

🧙 Contributors

Contributions of any kind welcome. Thanks goes to these wonderful people ❤️

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⭐ Show your support

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🐙 Community

• Stack Overflow
• Quora
• Spectrum community

🔗 Related Projects

This project is based on mini-css-extract-plugin and the amazing work of Tobias Koppers (@sokra) and other Webpack maintainers.

👨‍🔧 Maintainers

👤 Juro Oravec

• Twitter: @JuroOravec
• GitHub: @JuroOravec
• LinkedIn: @jurooravec
• Sourcerer: @JuroOravec

📝 License

Copyright © 2020 Juro Oravec.

This project is MIT licensed.