webpack-manifest-plugin

What is webpack-manifest-plugin?

The webpack-manifest-plugin is a Webpack plugin that generates an asset manifest file. This manifest maps the original filenames to the output filenames generated by Webpack, which is useful for integrating Webpack with server-side code and caching strategies.

What are webpack-manifest-plugin's main functionalities?

Generate a manifest file

This feature generates a manifest file that maps the original filenames to the output filenames. The 'fileName' option specifies the name of the manifest file, 'basePath' is a path prefix for all keys, and 'publicPath' is a path prefix for all values.

const WebpackManifestPlugin = require('webpack-manifest-plugin');

module.exports = {
  // ... other webpack config settings ...
  plugins: [
    new WebpackManifestPlugin({
      fileName: 'manifest.json',
      basePath: '/app/',
      publicPath: '/public/'
    })
  ]
};

Filter files

This feature allows filtering of files to be included in the manifest based on custom logic. In this example, only JavaScript and CSS files are included.

new WebpackManifestPlugin({
  filter: (file) => {
    // Only include .js and .css files in the manifest
    return file.name.match(/\.(js|css)$/);
  }
});

Customize manifest entries

This feature allows customization of how the manifest entries are generated. In this example, the 'generate' function is used to create a custom structure for the manifest.

new WebpackManifestPlugin({
  generate: (seed, files) => {
    return files.reduce((manifest, file) => {
      manifest[file.name] = file.path;
      return manifest;
    }, seed);
  }
});

Other packages similar to webpack-manifest-plugin

assets-webpack-plugin

Similar to webpack-manifest-plugin, assets-webpack-plugin also generates a manifest file with the mapping of all source file names to their corresponding output file. However, it provides more options for customizing the output, such as different file formats (JSON, YAML, etc.) and the ability to include additional information like chunk relations.

webpack-assets-manifest

This package is a similar plugin that creates a JSON file that maps the original filenames to the output filenames. It has features like HMR support, customizable output using hooks, and the ability to merge with an existing manifest file.

webpack-pwa-manifest

While it also generates a manifest, webpack-pwa-manifest is specifically focused on creating the manifest.json file for Progressive Web Apps (PWAs), including icons and other PWA-related configurations, which is different from the general asset mapping provided by webpack-manifest-plugin.

README

webpack-manifest-plugin

A Webpack plugin for generating an asset manifest.

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Requirements

webpack-manifest-plugin is an evergreen 🌲 module.

This module requires an Active LTS Node version (v10.0.0+) and Webpack v4.44.0+.

Install

Using npm:

npm install webpack-nano webpack-manifest-plugin --save-dev

Note: We recommend using webpack-nano, a very tiny, very clean webpack CLI.

Usage

Create a webpack.config.js file:

const { WebpackManifestPlugin } = require('webpack-manifest-plugin');
const options = { ... };

module.exports = {
	// an example entry definition
	entry: [ 'app.js'	],
  ...
  plugins: [
    new WebpackManifestPlugin(options)
  ]
};

And run webpack:

$ npx wp
...

With the default options, the example above will create a `manifest.json` file in the output directory for the build. The manfist file will contain a map of source filenames to the corresponding build output file. e.g.

```json
{
  "dist/batman.js": "dist/batman.1234567890.js",
  "dist/joker.js": "dist/joker.0987654321.js"
}

Options

basePath

Type: String
Default: ''

Specifies a path prefix for all keys in the manifest. Useful for including your output path in the manifest.

fileName

Type: String
Default: manifest.json

Specifies the file name to use for the resulting manifest. By default the plugin will emit manifest.json to your output directory. Passing an absolute path to the fileName option will override both the file name and path.

filter

Type: Function
Default: undefined

Allows filtering the files which make up the manifest. The passed function should match the signature of (file: FileDescriptor) => Boolean. Return true to keep the file, false to remove the file.

generate

Type: Function
Default: undefined

A custom Function to create the manifest. The passed function should match the signature of (seed: Object, files: FileDescriptor[], entries: string[]) => Object and can return anything as long as it's serialisable by JSON.stringify.

map

Type: Function
Default: undefined

Allows modifying the files which make up the manifest. The passed function should match the signature of (file: FileDescriptor) => FileDescriptor where an object matching FileDescriptor is returned.

publicPath

Type: String
Default: <webpack-config>.output.publicPath

A path prefix that will be added to values of the manifest.

removeKeyHash

Type: RegExp | Boolean
Default: /([a-f0-9]{32}\.?)/gi

If set to a valid RegExp, removes hashes from manifest keys. e.g.

{
  "index.c5a9bff71fdfed9b6046.html": "index.c5a9bff71fdfed9b6046.html"
}

{
  "index.html": "index.c5a9bff71fdfed9b6046.html"
}

The default value for this option is a regular expression targeting Webpack's default md5 hash. To target other hashing functions / algorithms, set this option to an appropriate RegExp. To disable replacing the hashes in key names, set this option to false.

seed

Type: Object
Default: {}

A cache of key/value pairs to used to seed the manifest. This may include a set of custom key/value pairs to include in your manifest, or may be used to combine manifests across compilations in multi-compiler mode. To combine manifests, pass a shared seed object to each compiler's WebpackManifestPlugin instance.

serialize

Type: Function(Object) => string
Default: undefined

A Function which can be leveraged to serialize the manifest in a different format than json. e.g. yaml.

sort

Type: Function
Default: undefined

Allows sorting the files which make up the manifest. The passed function should match the signature of (fileA: FileDescriptor, fileB: FileDescriptor) => Number. Return 0 to indicate no change, -1 to indicate the file should be moved to a lower index, and 1 to indicate the file shoud be moved to a higher index.

useEntryKeys

Type: Boolean
Default: false

If true, the keys specified in the entry property will be used as keys in the manifest. No file extension will be added (unless specified as part of an entry property key).

writeToFileEmit

Type: Boolean
Default: false

If true, will emit the manifest to the build directory and in memory for compatibility with webpack-dev-server.

Manifest File Descriptor

This plugin utilizes the following object structure to work with files. Many options for this plugin utilize the structure below.

{
  chunk?: Chunk;
  isAsset: boolean;
  isChunk: boolean;
  isInitial: boolean;
  isModuleAsset: boolean;
  name: string | null;
  path: string;
}

chunk

Type: Chunk

Only available if isChunk is true

isInitial

Type: Boolean

Is required to run you app. Cannot be true if isChunk is false.

isModuleAsset

Type: Boolean

Is required by a module. Cannot be true if isAsset is false.

Compiler Hooks

This plugin supports the following hooks via the getCompilerHooks export; afterEmit, beforeEmit. These hooks can be useful, e.g. changing manifest contents before emitting to disk.

getCompilerHooks

Returns: { afterEmit: SyncWaterfallHook, beforeEmit: SyncWaterfallHook }

Usage

const { getCompilerHooks } = require('webpack-manifest-plugin');

class BatmanPlugin {
  apply(compiler) {
    const { beforeEmit } = getCompilerHooks(compiler);

    beforeEmit.tap('BatmanPlugin', (manifest) => {
      return { ...manifest, name: 'hello' };
    })
  }
}

Attiribution

Special thanks to Dane Thurber, the original author of this plugin, without whom this plugin would not exist.

Meta

CONTRIBUTING

LICENSE (MIT)