assets-webpack-plugin
Webpack plugin that emits a json file with assets paths.
Table of Contents
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