Demos:
Bundle analysis comparison ·
Bundle analysis

BundleStats webpack plugin

Analyze bundle stats(bundle size, assets, modules, packages) and compare the results between different builds. Support for webpack, rspack, vite, rollup and rolldown.

- Bundle size and totals by file type(css, js, img, etc)

- Insights: duplicate packages, new packages

- Initial JS/CSS, Cache invalidation, and other bundle metrics

- Assets report (entrypoint, initial, types, changed, delta)

- Modules report (changed, delta, chunks, duplicate count and percentage)

- Packages report (count, duplicate, changed, delta)

:star: Side by side comparison for multiple builds

Table of Contents

- Install
- Webpack configuration
- BundleStatsWebpackPlugin(options)
- Use with create-react-app
- Compare mode
- Other packages
- Related projects

Install

``shell
npm install --dev bundle-stats-webpack-plugin
`

or

`shell
yarn add --dev bundle-stats-webpack-plugin
`

Webpack configuration

`js
// webpack.config.js
const { BundleStatsWebpackPlugin } = require('bundle-stats-webpack-plugin');

module.exports = {
...,
plugins: [
new BundleStatsWebpackPlugin()
]
}
`


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- compare - use local saved baseline for comparison (default true).
- baseline - save current webpack stats as baseline (default false).
- html - output html report (default true).
- json - output json report (default false).
- outDir - output directory relative to webpack output.path (default '').
- baselineFilepath - baseline filepath relative to webpack output.path (default 'node_modules/.cache/bundle-stats/baseline.json')
- silent - stop logging info and only log warning and error (default false).
- stats - Webpack stats options
default:
`js
// webpack.config.js
module.exports = {
// ...
stats: {
assets: true,
chunks: true,
modules: true,
builtAt: true,
hash: true,
},
};
`

How to configure webpack for better debugging and monitoring

#### How to exclude virtual modules

Some plugins use virtual modules as an intermediary step when generating JS modules. For example, vanilla-extract creates a virtual module for every .css.js/css.ts file based on the loader module path and the filename/source as query parameters:

`
./node_modules/@vanilla-extract/webpack-plugin/vanilla.virtual.css?%7B%22fileName%22%3A%22src%2Fcomponents%2Fcomponent%2Fcomponent.css.ts.vanilla.css%22%2C%22source%22%3A%22...%22%7D
`

Inlining the encoded source and the filename causes an increase in the size of the output stats and adds unnecessary entries to the stats. To ignore vanilla-extract virtual modules from the stats and from the bundle analysis report, use excludeModules option:


`js
// webpack.config.js
module.exports = {
// ...
stats: {
excludeModules: [
/@vanilla-extract\/webpack-plugin\/vanilla-virtual\.css/,
],
},
};
`

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You will need to customize the default webpack config. That can be done by using react-app-rewired which is one of create-react-app's custom config solutions. You will also need customize-cra.

`shell
npm install --dev customize-cra react-app-rewired
`

or

`shell
yarn add customize-cra react-app-rewired --dev
`

Change your default scripts in package.json to:

`json
/ package.json /
"scripts": {
"start": "react-app-rewired start",
"build": "react-app-rewired build",
"test": "react-app-rewired test"
}
`

Create a file config-overrides.js at the same level as package.json.

`js
// config-overrides.js
const { override, addWebpackPlugin } = require('customize-cra');
const { BundleStatsWebpackPlugin } = require('bundle-stats-webpack-plugin');

module.exports = override(
addWebpackPlugin(new BundleStatsWebpackPlugin()),
);
`

Compare mode

In compare mode, the metrics are compared against an existing(node_modules/.cache/bundle-stats/baseline.json) Webpack stats file(baseline). To generate the baseline webpack stats, set BUNDLE_STATS_BASELINE environmental variable to true or set BundleStatsWebpackPlugin baseline option to true:

`shell


Checkout to the branch/tag/commit where you want to generate the baseline

$ git checkout master

Build your application with BUNDLE_STATS_BASELINE environmental variable

$ BUNDLE_STATS_BASELINE=true npm run build

Checkout to the working branch/tag/commit

$ git checkout MY_FEATURE_BRANCH

Build your application

$ npm run build
`

The option can be disabled by setting BundleStatsWebpackPlugin compare option to false`.

Other packages

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CLI to generate bundle stats report.

$3

 

Gatsby plugin for bundle-stats.

$3

 

Next.js plugin for bundle-stats.

$3

 

Rollup plugin to generate bundle stats report for vite/rolldown/rollup.

Related projects

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#### Automated bundle analysis, reviews and monitoring - Quickly identify and fix bundle regressions before shipping to production.

- :crystal_ball: In-depth bundle stats analysis for every build
- :chart_with_upwards_trend: Monitor bundle stats changes and identify opportunities for optimizations
- :bell: Quick feedback with rule based automated review flow, GitHub Pull Request comments, GitHub check reports, or Slack messages
- :wrench: Support for webpack, vite, rspack, rollup, rolldown
- :hammer: Support for all major CI services(CircleCI, GitHub Actions, Gitlab CI, Jenkins, Travis CI)
- :nut_and_bolt: Support for npm, yarn and pnpm; support for monorepos
- :two_hearts: Always free for Open Source

:rocket: Get started

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Standalone web application to compare Webpack/Lighthouse/Browsertime stats.

Compare bundle stats

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Github Action that generates bundle-stats reports.