Webpack plugin that emits a json file with assets paths.
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.
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"
}
}
npm install assets-webpack-plugin --save-dev
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]
}
You can pass the following options:
filename: Name for the created json file. Defaults to webpack-assets.json
new AssetsPlugin({filename: 'assets.json'})
fullPath: 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: Inserts the manifest javascript as a text
property in your assets.
False by default. 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.
// webpack.config.js
new AssetsPlugin({includeManifest: 'manifest'});
//assets.json
{entries: {manifest: {js: `hashed_manifest.js`, text: 'function(modules)...'}}}
// your html template
<script>
{assets.entries.manifest.text}
</script>
path: Path where to save the created json file. Defaults to the current directory.
new AssetsPlugin({path: path.join(__dirname, 'app', 'views')})
prettyPrint: Whether to format the json output for readability. Defaults to false.
new AssetsPlugin({prettyPrint: true})
processOutput: Formats the assets output. Defaults is JSON stringify function.
new AssetsPlugin({
processOutput: function (assets) {
return 'window.staticMap = ' + JSON.stringify(assets)
}
})
update: When set to true, the output json file will be updated instead of overwritten. Defaults to false.
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}
// }
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]
}
])
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>
npm test