hooraygith / dm-webpack-assets-manifest

This Webpack plugin will generate a JSON file that matches the original filename with the hashed version.

Webpack Assets Manifest

This Webpack plugin will generate a JSON file that matches the original filename with the hashed version.

Installation

npm install webpack-assets-manifest --save

Usage

In your webpack config, require the plugin then add an instance to the plugins array.

new WebpackAssetsManifest({
  output: 'manifest.json',
  replacer: null,
  space: 2,
  writeToDisk: false,
  fileExtRegex: /\.\w{2,4}\.(?:map|gz)$|\.\w+$/i,
  sortManifest: true,
  merge: false,
  publicPath: ''
});

Options

option	type	default	description
assets	object	{}	Data is stored in this object.
output	string	manifest.json	Where to save the manifest file relative to your webpack output.path.
replacer	null, function, or array	null	Replacer reference
space	int	2	Number of spaces to use for pretty printing.
writeToDisk	boolean	false	Write the manifest to disk using fs during after-emit
fileExtRegex	regex	`/.\w{2,4}.(?:map	gz)$
sortManifest	boolean, function	true	Should the manifest be sorted? If a function is provided, it will be used as the comparison function.
merge	boolean	false	If the output file already exists, should the data be merged with it?
publicPath	string, function	''	Value prefix or callback to customize the value.

Using webpack-dev-server

If you're using another language for your site and you're using webpack-dev-server to process your assets during development, you should set writeToDisk to true and provide an absolute path in output so the manifest file is actually written to disk and not kept only in memory.

Sharing data

You can share data between instances by passing in your own object in the assets option. This is useful in multi-compiler mode.

var data = Object.create(null);

var manifest1 = new WebpackAssetsManifest({
  assets: data
});

var manifest2 = new WebpackAssetsManifest({
  assets: data
});

Merging data

If you have a json file you'd like to add to, you can do that with the merge option. If your json file is not in ${output.path}/manifest.json, you should specify where the file is with the output option.

new WebpackAssetsManifest({
  output: '/path/to/manifest.json',
  merge: true
});

Sorting the manifest

The manifest is sorted alphabetically by default. You can turn off sorting by setting sortManifest to false.

If you want more control over how the manifest is sorted, you can provide your own comparison function. In the example below, the manifest will be sorted by file extension then alphabetically.

new WebpackAssetsManifest({
  output: 'manifest.json',
  space: 2,
  sortManifest: function(a, b) {
    var extA = this.getExtension(a);
    var extB = this.getExtension(b);

    if ( extA > extB ) {
      return 1;
    }

    if ( extA < extB ) {
      return -1;
    }

    return a.localeCompare(b);
  }
});

Add your CDN

You can customize the value that gets saved to the manifest by using publicPath.

One common use is to prefix your CDN URL to the value.

var manifest = new WebpackAssetsManifest({
  publicPath: '//cdn.example.com'
});

If you'd like to have more control, use a function. The example below shows how you can prefix a different CDN based on the file extension.

var manifest = new WebpackAssetsManifest({
  publicPath: function( val, manifest ) {
    switch( manifest.getExtension( val ).substr(1).toLowerCase() ) {
      case 'jpg': case 'jpeg': case 'gif': case 'png': case 'svg':
        return '//img-cdn.example.com' + val;
        break;
      case 'css':
        return '//css-cdn.example.com' + val;
        break;
      case 'js':
        return '//js-cdn.example.com' + val;
        break;
      default:
        return '//cdn.example.com' + val;
    }
  }
});

---

Customizing the manifest

You can customize the manifest by adding your own event listeners. The manifest is passed as the first argument so you can do whatever you need to with it.

You can use has(key), get(key), set(key, value), and delete(key) methods on manifest plugin instance to manage what goes into the manifest.

var manifest = new WebpackAssetsManifest();

manifest.on('apply', function(manifest) {
  manifest.set('some-key', 'some-value');
});

manifest.on('done', function(manifest, stats) {
  console.log(`The manifest has been written to ${manifest.getOutputPath()}`);
  console.log(stats); // Compilation stats
});

These event listeners can also be set by passing them in the constructor options.

new WebpackAssetsManifest({
  done: function(manifest, stats) {
    console.log(`The manifest has been written to ${manifest.getOutputPath()}`);
    console.log(stats); // Compilation stats
  }
});

Events

name	listener signature
apply	function(manifest){}
moduleAsset	function(manifest, key, hashedFile, module){}
processAssets	function(manifest, assets){}
done	function(manifest, stats){}

---

Example config

In this example, manifest.json will be saved in the folder defined in output.path.

var WebpackAssetsManifest = require('webpack-assets-manifest');

module.exports = {
  entry: {
    main: "./your-main-file",
  },

  output: {
    path: path.join( __dirname, 'public', 'assets' ),
    filename: '[name]-[hash].js',
    chunkFilename: '[id]-[hash].js',
    publicPath: 'assets/'
  },

  module: {
    // Your loader rules go here.
  },

  plugins: [
    new WebpackAssetsManifest()
  ]
};

---

Sample output

{
  "main.js": "main-9c68d5e8de1b810a80e4.js",
  "main.css": "main-9c68d5e8de1b810a80e4.css",
  "images/logo.svg": "images/logo-b111da4f34cefce092b965ebc1078ee3.svg"
}