assets-webpack-plugin

What is assets-webpack-plugin?

The assets-webpack-plugin is a Webpack plugin that generates a JSON file containing the paths of the output files. This is useful for server-side rendering or when you need to inject the assets into your HTML manually.

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

Generate JSON file with asset paths

This feature allows you to generate a JSON file that contains the paths of the output files. This is useful for server-side rendering or when you need to inject the assets into your HTML manually.

const AssetsWebpackPlugin = require('assets-webpack-plugin');

module.exports = {
  // other webpack configuration
  plugins: [
    new AssetsWebpackPlugin({
      path: path.join(__dirname, 'dist'),
      filename: 'assets.json'
    })
  ]
};

Customizing the output format

This feature allows you to customize the format of the generated JSON file. For example, you can enable pretty printing to make the JSON file more readable.

const AssetsWebpackPlugin = require('assets-webpack-plugin');

module.exports = {
  // other webpack configuration
  plugins: [
    new AssetsWebpackPlugin({
      path: path.join(__dirname, 'dist'),
      filename: 'assets.json',
      prettyPrint: true
    })
  ]
};

Including additional information

This feature allows you to include additional information in the generated JSON file. For example, you can specify which file types to include in the JSON file.

const AssetsWebpackPlugin = require('assets-webpack-plugin');

module.exports = {
  // other webpack configuration
  plugins: [
    new AssetsWebpackPlugin({
      path: path.join(__dirname, 'dist'),
      filename: 'assets.json',
      includeAllFileTypes: false,
      fileTypes: ['js', 'css']
    })
  ]
};

Other packages similar to assets-webpack-plugin

html-webpack-plugin

The html-webpack-plugin simplifies the creation of HTML files to serve your webpack bundles. It automatically injects the output files into the HTML file. Unlike assets-webpack-plugin, which generates a JSON file with asset paths, html-webpack-plugin directly creates an HTML file with the necessary script and link tags.

webpack-manifest-plugin

The webpack-manifest-plugin generates a manifest file that maps the original filenames to the hashed filenames. This is similar to assets-webpack-plugin, but it focuses on creating a manifest file for cache busting and long-term caching.

webpack-assets-manifest

The webpack-assets-manifest plugin generates a JSON file that maps the original filenames to the hashed filenames, similar to assets-webpack-plugin. However, it provides more customization options and supports merging with existing manifest files.

README

assets-webpack-plugin

Webpack plugin that emits a json file with assets paths.

Table of Contents

• Why Is This Useful?

• Install

• Configuration

• Test

• Change Log

• Contributing Guidelines

Why Is This Useful?

When working with Webpack you might want to generate your bundles with a generated hash in them (for cache busting).

This plug-in outputs a json file with the paths of the generated assets so you can find them from somewhere else.

Example output:

The output is a JSON object in the form:

{
    "bundle_name": {
        "asset_kind": "/public/path/to/asset"
    }
}

Where:

• "bundle_name" is the name of the bundle (the key of the entry object in your webpack config, or "main" if your entry is an array).
• "asset_kind" is the camel-cased file extension of the asset

For example, given the following webpack config:

{
    entry: {
        one: ['src/one.js'],
        two: ['src/two.js']
    },
    output: {
        path: path.join(__dirname, "public", "js"),
        publicPath: "/js/",
        filename: '[name]_[hash].bundle.js'
    }
}

The plugin will output the following json file:

{
    "one": {
        "js": "/js/one_2bb80372ebe8047a68d4.bundle.js"
    },
    "two": {
        "js": "/js/two_2bb80372ebe8047a68d4.bundle.js"
    }
}

Install

npm install assets-webpack-plugin --save-dev

Configuration

In your webpack config include the plug-in. And add it to your config:

var path = require('path')
var AssetsPlugin = require('assets-webpack-plugin')
var assetsPluginInstance = new AssetsPlugin()

module.exports = {
    // ...
    output: {
        path: path.join(__dirname, "public", "js"),
        filename: "[name]-bundle-[hash].js",
        publicPath: "/js/"
    },
    // ....
    plugins: [assetsPluginInstance]
}

Options

You can pass the following options:

filename

Optional. webpack-assets.json by default.

Name for the created json file.

new AssetsPlugin({filename: 'assets.json'})

fullPath

Optional. true by default.

If false the output will not include the full path of the generated file.

new AssetsPlugin({fullPath: false})

e.g.

/public/path/bundle.js vs bundle.js vs

includeManifest

Optional. false by default.

Inserts the manifest javascript as a text property in your assets. Accepts the name of your manifest chunk. A manifest is the last CommonChunk that only contains the webpack bootstrap code. This is useful for production use when you want to inline the manifest in your HTML skeleton for long-term caching. See issue #1315 or a blog post to learn more.

new AssetsPlugin({includeManifest: 'manifest'})
// assets.json:
// {entries: {manifest: {js: `hashed_manifest.js`, text: 'function(modules)...'}}}
//
// Your html template:
// <script>
// {assets.entries.manifest.text}
// </script>

manifestFirst

Optional. false by default.

Orders the assets output so that manifest is the first entry. This is useful for cases where script tags are generated from the assets json output, and order of import is important.

new AssetsPlugin({manifestFirst: true})

path

Optional. Defaults to the current directory.

Path where to save the created JSON file. Will default to the highest level of the project unless useCompilerPath is specified.

new AssetsPlugin({path: path.join(__dirname, 'app', 'views')})

useCompilerPath

new AssetsPlugin({useCompilerPath: true})

Will override the path to use the compiler output path set in your webpack config.

prettyPrint

Optional. false by default.

Whether to format the JSON output for readability.

new AssetsPlugin({prettyPrint: true})

processOutput

Optional. Defaults is JSON stringify function.

Formats the assets output.

new AssetsPlugin({
  processOutput: function (assets) {
    return 'window.staticMap = ' + JSON.stringify(assets)
  }
})

update

Optional. false by default.

When set to true, the output JSON file will be updated instead of overwritten.

new AssetsPlugin({update: true})

metadata

Inject metadata into the output file. All values will be injected into the key "metadata".

new AssetsPlugin({metadata: {version: 123}})
// Manifest will now contain:
// {
//   metadata: {version: 123}
// }

includeAllFileTypes

Optional. true by default.

When set false, falls back to the fileTypes option array to decide which file types to include in the assets file.

new AssetsPlugin({includeAllFileTypes: false})

fileTypes

Optional. ['js', 'css'] by default.

When set and includeAllFileTypes is set false, only assets matching these types will be included in the assets file.

new AssetsPlugin({fileTypes: ['js', 'jpg']})

keepInMemory

Optional. false by default.

When set the assets file will only be generated in memory while running webpack-dev-server and not written to disk.

new AssetsPlugin({keepInMemory: true})

integrity

Optional. false by default.

When set the output from webpack-subresource-integrity is included in the assets file.

Please make sure you have webpack-subresource-integrity installed and included in your webpack plugins.

new AssetsPlugin({integrity: true})

Output will now look like this:

{
  "main": {
    "js": "/bundle.js",
    "jsIntegrity": "sha256-ANGwtktWN96nvBI/cjekdTvd0Dwf7SciIFTQ2lpTxGc= sha384-Ly439pF3K+J8hnhk1BEcjKnv1R9BApFYVIVJvr64PcgBjdT4N7hfPzQynItHwcaO"
  },
  "vendors~main": {
    "js": "/1.bundle.js",
    "jsIntegrity": "sha256-yqNi1hgeAdkXVOORgmVMeX+cbuXikoj6I8qWZjPegsA= sha384-4X75tnsGDwnwL5kBUPsx2ko9DeWy0xM8BcDQdoR185yho+OnxjjPXl2wCdebLWTG"
  }
}

entrypoints

Optional. false by default.

If the 'entrypoints' option is given, the output will be limited to the entrypoints and the chunks associated with them.

new AssetsPlugin({entrypoints: true})

Using in multi-compiler mode

If you use webpack multi-compiler mode and want your assets written to a single file, you must use the same instance of the plugin in the different configurations.

For example:

var webpack = require('webpack')
var AssetsPlugin = require('assets-webpack-plugin')
var assetsPluginInstance = new AssetsPlugin()

webpack([
  {
    entry: {one: 'src/one.js'},
    output: {path: 'build', filename: 'one-bundle.js'},
    plugins: [assetsPluginInstance]
  },
  {
    entry: {two:'src/two.js'},
    output: {path: 'build', filename: 'two-bundle.js'},
    plugins: [assetsPluginInstance]
  }
])

Using this with Rails

You can use this with Rails to find the bundled Webpack assets via Sprockets. In ApplicationController you might have:

def script_for(bundle)
  path = Rails.root.join('app', 'views', 'webpack-assets.json') # This is the file generated by the plug-in
  file = File.read(path)
  json = JSON.parse(file)
  json[bundle]['js']
end

Then in the actions:

def show
  @script = script_for('clients') # this will retrieve the bundle named 'clients'
end

And finally in the views:

<div id="app">
  <script src="<%= @script %>"></script>
</div>

Using this with ASP.NET Core

You can use this with ASP.NET Core via the WebpackTag library.

Test

npm test

Changelog

5.0.2 - 2020-06-15

• Fixes an error when keepInMemory was turn on.