What is webpack-stats-plugin?
The webpack-stats-plugin is a plugin for Webpack that allows you to generate and customize the stats output of your Webpack build process. This can be useful for analyzing the build performance, understanding the structure of your bundles, and debugging issues.
What are webpack-stats-plugin's main functionalities?
Generate Stats JSON
This feature allows you to generate a JSON file containing detailed statistics about your Webpack build. The `StatsWriterPlugin` is configured to output a `stats.json` file with information about assets, chunks, and modules.
const { StatsWriterPlugin } = require('webpack-stats-plugin');
module.exports = {
plugins: [
new StatsWriterPlugin({
filename: 'stats.json',
stats: {
all: false,
assets: true,
chunks: true,
modules: true,
},
}),
],
};
Custom Stats Output
This feature allows you to customize the output of the stats file. The `transform` function is used to modify the data before it is written to the file. In this example, the output JSON file will contain only the assets and module names.
const { StatsWriterPlugin } = require('webpack-stats-plugin');
module.exports = {
plugins: [
new StatsWriterPlugin({
filename: 'custom-stats.json',
transform(data, opts) {
return JSON.stringify({
assets: data.assetsByChunkName,
modules: data.modules.map(module => module.name),
}, null, 2);
},
}),
],
};
Other packages similar to webpack-stats-plugin
webpack-bundle-analyzer
The webpack-bundle-analyzer plugin provides a visual representation of the contents of your bundles. It generates an interactive treemap visualization of the contents of all your bundles, which can help you understand the size and composition of your bundles. Unlike webpack-stats-plugin, which focuses on generating stats files, webpack-bundle-analyzer provides a more visual and interactive way to analyze your bundles.
webpack-dashboard
The webpack-dashboard plugin provides a terminal-based dashboard for your Webpack build process. It displays real-time information about the build, including progress, errors, and warnings. This can be useful for getting a quick overview of the build process without having to dig into stats files. Compared to webpack-stats-plugin, webpack-dashboard is more focused on providing real-time feedback during the build process.
speed-measure-webpack-plugin
The speed-measure-webpack-plugin measures the build time of your Webpack plugins and loaders. It provides detailed timing information that can help you identify performance bottlenecks in your build process. While webpack-stats-plugin focuses on generating detailed stats about the build output, speed-measure-webpack-plugin is specifically designed to help you optimize the build performance.
Webpack Stats Plugin
This plugin will ingest the webpack
stats object,
process / transform the object and write out to a file for further consumption.
The most common use case is building a hashed bundle and wanting to
programmatically refer to the correct bundle path in your Node.js server.
Installation
The plugin is available via npm:
$ npm install --save-dev webpack-stats-plugin
$ yarn add --dev webpack-stats-plugin
Examples
We have example webpack configurations for all versions of webpack. See., e.g.
test/webpack4/webpack.config.js
.
CLI
If you are using webpack-cli
, you can enable with:
$ webpack-cli --plugin webpack-stats-plugin/lib/stats-writer-plugin
Basic
A basic webpack.config.js
-based integration:
const { StatsWriterPlugin } = require("webpack-stats-plugin")
module.exports = {
plugins: [
new StatsWriterPlugin({
filename: "stats.json"
})
]
}
Custom stats
Configuration
This option is passed to the webpack compiler's getStats().toJson()
method.
const { StatsWriterPlugin } = require("webpack-stats-plugin")
module.exports = {
plugins: [
new StatsWriterPlugin({
stats: {
all: false,
assets: true
}
})
]
}
Custom Transform Function
The transform function has a signature of:
function (data, opts) {}
which you can use like:
const { StatsWriterPlugin } = require("webpack-stats-plugin");
module.exports = {
plugins: [
new StatsWriterPlugin({
transform(data, opts) {
return JSON.stringify({
main: data.assetsByChunkName.main[0],
css: data.assetsByChunkName.main[1]
}, null, 2);
}
})
]
}
Promise transform
You can use an asynchronous promise to transform as well:
const { StatsWriterPlugin } = require("webpack-stats-plugin");
module.exports = {
plugins: [
new StatsWriterPlugin({
filename: "stats-transform-promise.json",
transform(data) {
return Promise.resolve().then(() => JSON.stringify({
main: data.assetsByChunkName.main
}, null, INDENT));
}
})
]
}
Plugins
StatsWriterPlugin(opts)
- opts (
Object
) options - opts.filename (
String
) output file name (Default: "stats.json"
) - opts.fields (
Array
) fields of stats obj to keep (Default: ["assetsByChunkName"]
) - opts.stats (
Object|String
) stats config object or string preset (Default: {}
) - opts.transform (
Function|Promise
) transform stats obj (Default: JSON.stringify()
)
Stats writer module.
Stats can be a string or array (we'll have an array due to source maps):
"assetsByChunkName": {
"main": [
"cd6371d4131fbfbefaa7.bundle.js",
"../js-map/cd6371d4131fbfbefaa7.bundle.js.map"
]
},
Note: The stats object is big. It includes the entire source included
in a bundle. Thus, we default opts.fields
to ["assetsByChunkName"]
to
only include those. However, if you want the whole thing (maybe doing an
opts.transform
function), then you can set fields: null
in options to
get all of the stats object.
You may also pass a custom stats config object (or string preset) via opts.stats
in order to select exactly what you want added to the data passed to the transform.
When opts.stats
is passed, opts.fields
will default to null
.
See:
filename
: The opts.filename
option can be a file name or path relative to
output.path
in webpack configuration. It should not be absolute.
transform
: By default, the retrieved stats object is JSON.stringify
'ed
but by supplying an alternate transform you can target any output format.
See test/webpack4/webpack.config.js
for
various examples including Markdown output.
- Warning: The output of
transform
should be a String
, not an object. On
Node v4.x
if you return a real object in transform
, then webpack will
break with a TypeError
(See
#8). Just
adding a simple JSON.stringify()
around your object is usually what you need
to solve any problems.
Contributions
Contributions welcome!
We test against all versions of webpack. For a full explanation of our
functional tests, see test/README.md
To get started, first install:
$ yarn
Our tests first do various webpack builds and then run mocha asserts on the real
outputted stats files. Inefficient, but for our small sample size efficient
enough.
$ yarn run lint
$ yarn run test
$ yarn run check
Maintenance Status
Active: Formidable is actively working on this project, and we expect to continue for work for the foreseeable future. Bug reports, feature requests and pull requests are welcome.