webpack-bundle-analyzer
Webpack plugin and CLI utility that represents bundle content as convenient interactive zoomable treemap
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A bundler for javascript and friends. Packs many modules into a few bundled assets. Code Splitting allows for loading parts of the application on demand. Through "loaders", modules can be CommonJs, AMD, ES6 modules, CSS, Images, JSON, Coffeescript, LESS, ... and your custom stuff.
The zero configuration build tool for the web. 📦🚀
Next-generation ES module bundler
An extremely fast bundler for the web
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Quick Overview
Webpack Bundle Analyzer is a plugin for Webpack that visualizes the size of webpack output files with an interactive zoomable treemap. It helps developers analyze and optimize their JavaScript bundles by providing a clear visual representation of the bundle's composition and size.
Pros
- Provides an intuitive, interactive visualization of bundle contents
- Helps identify large dependencies and potential areas for optimization
- Supports various output formats (static HTML, JSON, stats file)
- Easy to integrate into existing Webpack configurations
Cons
- Can significantly increase build time, especially for large projects
- May require additional configuration for accurate results with code splitting
- Limited customization options for the generated report
- Occasional issues with parsing certain types of modules or dependencies
Code Examples
- Basic usage in webpack.config.js:
const BundleAnalyzerPlugin = require('webpack-bundle-analyzer').BundleAnalyzerPlugin;
module.exports = {
plugins: [
new BundleAnalyzerPlugin()
]
}
- Generating a static report:
new BundleAnalyzerPlugin({
analyzerMode: 'static',
reportFilename: 'report.html',
openAnalyzer: false
})
- Customizing the analysis:
new BundleAnalyzerPlugin({
analyzerMode: 'server',
analyzerHost: '127.0.0.1',
analyzerPort: 8888,
defaultSizes: 'gzip',
excludeAssets: /\.map$/
})
Getting Started
-
Install the plugin:
npm install --save-dev webpack-bundle-analyzer
-
Add the plugin to your webpack.config.js:
const BundleAnalyzerPlugin = require('webpack-bundle-analyzer').BundleAnalyzerPlugin; module.exports = { plugins: [ new BundleAnalyzerPlugin() ] }
-
Run your Webpack build as usual. The analyzer will automatically open in your default browser.
Competitor Comparisons
A bundler for javascript and friends. Packs many modules into a few bundled assets. Code Splitting allows for loading parts of the application on demand. Through "loaders", modules can be CommonJs, AMD, ES6 modules, CSS, Images, JSON, Coffeescript, LESS, ... and your custom stuff.
Pros of webpack
- Core bundling functionality with extensive plugin ecosystem
- Highly configurable and customizable for complex build processes
- Active development and large community support
Cons of webpack
- Steeper learning curve, especially for complex configurations
- Can be overkill for smaller projects or simple bundling needs
- Performance can be slower for large projects without optimization
Code Comparison
webpack configuration:
module.exports = {
entry: './src/index.js',
output: {
filename: 'bundle.js',
path: path.resolve(__dirname, 'dist'),
},
};
webpack-bundle-analyzer usage:
const BundleAnalyzerPlugin = require('webpack-bundle-analyzer').BundleAnalyzerPlugin;
module.exports = {
plugins: [new BundleAnalyzerPlugin()]
};
Key Differences
- webpack is a full-featured module bundler, while webpack-bundle-analyzer is a plugin for analyzing bundle content
- webpack-bundle-analyzer focuses on visualizing bundle size and composition
- webpack provides the core bundling functionality, while webpack-bundle-analyzer helps optimize and understand bundle output
Use Cases
- Use webpack for bundling and building your entire project
- Use webpack-bundle-analyzer as a development tool to optimize bundle size and identify large dependencies
Integration
webpack-bundle-analyzer can be easily integrated into an existing webpack configuration as a plugin, providing valuable insights without changing the core bundling process.
The zero configuration build tool for the web. 📦🚀
Pros of Parcel
- Zero configuration required for most projects, making it easier to set up and use
- Faster build times due to its out-of-the-box optimizations and caching
- Built-in support for various file types without additional plugins
Cons of Parcel
- Less flexibility and customization options compared to Webpack ecosystem
- Smaller community and ecosystem, which may result in fewer resources and third-party integrations
- May not be suitable for complex projects that require fine-grained control over the build process
Code Comparison
Webpack Bundle Analyzer configuration:
const BundleAnalyzerPlugin = require('webpack-bundle-analyzer').BundleAnalyzerPlugin;
module.exports = {
plugins: [new BundleAnalyzerPlugin()]
};
Parcel doesn't require configuration for basic usage:
parcel build entry.js
Summary
Parcel offers a simpler, zero-configuration approach to bundling, making it ideal for smaller projects or quick prototypes. It provides faster build times and built-in support for various file types. However, it lacks the extensive ecosystem and customization options of Webpack.
Webpack Bundle Analyzer, being a plugin for Webpack, benefits from Webpack's flexibility and large ecosystem. It provides detailed insights into bundle composition but requires more configuration and setup compared to Parcel's out-of-the-box functionality.
Choose Parcel for simplicity and speed in smaller projects, and Webpack with Bundle Analyzer for complex projects requiring detailed bundle analysis and customization.
Next-generation ES module bundler
Pros of Rollup
- Simpler configuration and faster build times for smaller projects
- Better tree-shaking capabilities, resulting in smaller bundle sizes
- Native ES module support, making it ideal for library authors
Cons of Rollup
- Less extensive plugin ecosystem compared to Webpack
- Limited code-splitting capabilities out of the box
- May require additional setup for handling non-JavaScript assets
Code Comparison
Rollup configuration:
export default {
input: 'src/main.js',
output: {
file: 'bundle.js',
format: 'iife'
}
};
webpack-bundle-analyzer usage:
const BundleAnalyzerPlugin = require('webpack-bundle-analyzer').BundleAnalyzerPlugin;
module.exports = {
plugins: [new BundleAnalyzerPlugin()]
};
While Rollup focuses on simplicity and efficient bundling for ES modules, webpack-bundle-analyzer is a specialized tool for visualizing and analyzing Webpack bundle contents. Rollup is a complete bundler, whereas webpack-bundle-analyzer is a plugin for Webpack. The code examples show the basic configuration for Rollup and how to integrate webpack-bundle-analyzer into a Webpack configuration.
An extremely fast bundler for the web
Pros of esbuild
- Significantly faster build times due to its Go-based implementation
- Supports a wide range of modern JavaScript and TypeScript features out of the box
- Simpler configuration and API compared to webpack ecosystem
Cons of esbuild
- Less mature ecosystem and plugin support compared to webpack
- Limited customization options for advanced use cases
- May not support some legacy browser compatibility features
Code Comparison
esbuild:
require('esbuild').build({
entryPoints: ['app.js'],
bundle: true,
outfile: 'out.js',
}).catch(() => process.exit(1))
webpack-bundle-analyzer:
const BundleAnalyzerPlugin = require('webpack-bundle-analyzer').BundleAnalyzerPlugin;
module.exports = {
plugins: [new BundleAnalyzerPlugin()]
}
Key Differences
- webpack-bundle-analyzer focuses on analyzing and visualizing bundle contents, while esbuild is a full-featured bundler and minifier
- esbuild prioritizes speed and simplicity, while webpack-bundle-analyzer offers detailed insights into bundle composition
- webpack-bundle-analyzer integrates with the webpack ecosystem, whereas esbuild is a standalone tool that can be used independently or with other build systems
Use Cases
- Use esbuild for fast, straightforward bundling of modern JavaScript/TypeScript projects
- Choose webpack-bundle-analyzer when you need in-depth analysis of bundle size and composition in a webpack-based project
Build system optimized for JavaScript and TypeScript, written in Rust
Pros of Turborepo
- Designed for monorepo management, offering broader project organization capabilities
- Provides intelligent caching and parallel execution for faster builds
- Supports multiple package managers and languages
Cons of Turborepo
- Steeper learning curve due to its more complex feature set
- May be overkill for smaller projects or those not using monorepo structures
- Less focused on bundle analysis compared to webpack-bundle-analyzer
Code Comparison
Turborepo (turbo.json):
{
"pipeline": {
"build": {
"dependsOn": ["^build"],
"outputs": ["dist/**", ".next/**"]
},
"test": {
"dependsOn": ["build"],
"outputs": []
}
}
}
webpack-bundle-analyzer (webpack.config.js):
const BundleAnalyzerPlugin = require('webpack-bundle-analyzer').BundleAnalyzerPlugin;
module.exports = {
plugins: [
new BundleAnalyzerPlugin()
]
}
While webpack-bundle-analyzer focuses specifically on analyzing and visualizing webpack bundles, Turborepo is a more comprehensive tool for managing monorepo projects. Turborepo offers features like intelligent caching and parallel execution, which can significantly speed up build processes in large projects. However, it may be more complex to set up and use compared to the straightforward integration of webpack-bundle-analyzer.
Next generation frontend tooling. It's fast!
Pros of Vite
- Faster build times and hot module replacement (HMR) due to native ES modules
- Simpler configuration and setup out of the box
- Built-in support for TypeScript, JSX, and CSS pre-processors
Cons of Vite
- Less mature ecosystem and plugin availability compared to webpack
- May require additional configuration for complex projects
- Limited support for older browsers without modern JavaScript features
Code Comparison
Vite configuration:
// vite.config.js
export default {
build: {
rollupOptions: {
output: {
manualChunks: {
vendor: ['react', 'react-dom'],
},
},
},
},
}
webpack-bundle-analyzer configuration:
// webpack.config.js
const BundleAnalyzerPlugin = require('webpack-bundle-analyzer').BundleAnalyzerPlugin;
module.exports = {
plugins: [
new BundleAnalyzerPlugin()
]
}
While webpack-bundle-analyzer focuses specifically on bundle analysis, Vite is a complete build tool with built-in development server and optimization features. Vite's approach to bundling and serving assets during development leads to faster startup times and more efficient hot module replacement. However, webpack-bundle-analyzer offers more detailed and customizable bundle analysis, which can be particularly useful for large-scale projects with complex dependency structures.
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Webpack Bundle Analyzer
Visualize size of webpack output files with an interactive zoomable treemap.
Install
# NPM
npm install --save-dev webpack-bundle-analyzer
# Yarn
yarn add -D webpack-bundle-analyzer
Usage (as a plugin)
const BundleAnalyzerPlugin = require('webpack-bundle-analyzer').BundleAnalyzerPlugin;
module.exports = {
plugins: [
new BundleAnalyzerPlugin()
]
}
It will create an interactive treemap visualization of the contents of all your bundles.
This module will help you:
- Realize what's really inside your bundle
- Find out what modules make up the most of its size
- Find modules that got there by mistake
- Optimize it!
And the best thing is it supports minified bundles! It parses them to get real size of bundled modules. And it also shows their gzipped sizes!
Options (for plugin)
new BundleAnalyzerPlugin(options?: object)
Name | Type | Description |
---|---|---|
analyzerMode | One of: server , static , json , disabled | Default: server . In server mode analyzer will start HTTP server to show bundle report. In static mode single HTML file with bundle report will be generated. In json mode single JSON file with bundle report will be generated. In disabled mode you can use this plugin to just generate Webpack Stats JSON file by setting generateStatsFile to true . |
analyzerHost | {String} | Default: 127.0.0.1 . Host that will be used in server mode to start HTTP server. |
analyzerPort | {Number} or auto | Default: 8888 . Port that will be used in server mode to start HTTP server. If analyzerPort is auto , the operating system will assign an arbitrary unused port |
analyzerUrl | {Function} called with { listenHost: string, listenHost: string, boundAddress: server.address} . server.address comes from Node.js | Default: http://${listenHost}:${boundAddress.port} . The URL printed to console with server mode. |
reportFilename | {String} | Default: report.html . Path to bundle report file that will be generated in static mode. It can be either an absolute path or a path relative to a bundle output directory (which is output.path in webpack config). |
reportTitle | {String|function} | Default: function that returns pretty printed current date and time. Content of the HTML title element; or a function of the form () => string that provides the content. |
defaultSizes | One of: stat , parsed , gzip | Default: parsed . Module sizes to show in report by default. Size definitions section describes what these values mean. |
openAnalyzer | {Boolean} | Default: true . Automatically open report in default browser. |
generateStatsFile | {Boolean} | Default: false . If true , webpack stats JSON file will be generated in bundle output directory |
statsFilename | {String} | Default: stats.json . Name of webpack stats JSON file that will be generated if generateStatsFile is true . It can be either an absolute path or a path relative to a bundle output directory (which is output.path in webpack config). |
statsOptions | null or {Object} | Default: null . Options for stats.toJson() method. For example you can exclude sources of your modules from stats file with source: false option. See more options here. |
excludeAssets | {null|pattern|pattern[]} where pattern equals to {String|RegExp|function} | Default: null . Patterns that will be used to match against asset names to exclude them from the report. If pattern is a string it will be converted to RegExp via new RegExp(str) . If pattern is a function it should have the following signature (assetName: string) => boolean and should return true to exclude matching asset. If multiple patterns are provided asset should match at least one of them to be excluded. |
logLevel | One of: info , warn , error , silent | Default: info . Used to control how much details the plugin outputs. |
Usage (as a CLI utility)
You can analyze an existing bundle if you have a webpack stats JSON file.
You can generate it using BundleAnalyzerPlugin
with generateStatsFile
option set to true
or with this simple
command:
webpack --profile --json > stats.json
If you're on Windows and using PowerShell, you can generate the stats file with this command to avoid BOM issues:
webpack --profile --json | Out-file 'stats.json' -Encoding OEM
Then you can run the CLI tool.
webpack-bundle-analyzer bundle/output/path/stats.json
Options (for CLI)
webpack-bundle-analyzer <bundleStatsFile> [bundleDir] [options]
Arguments are documented below:
bundleStatsFile
Path to webpack stats JSON file
bundleDir
Directory containing all generated bundles.
options
-V, --version output the version number
-m, --mode <mode> Analyzer mode. Should be `server`, `static` or `json`.
In `server` mode analyzer will start HTTP server to show bundle report.
In `static` mode single HTML file with bundle report will be generated.
In `json` mode single JSON file with bundle report will be generated. (default: server)
-h, --host <host> Host that will be used in `server` mode to start HTTP server. (default: 127.0.0.1)
-p, --port <n> Port that will be used in `server` mode to start HTTP server. Should be a number or `auto` (default: 8888)
-r, --report <file> Path to bundle report file that will be generated in `static` mode. (default: report.html)
-t, --title <title> String to use in title element of html report. (default: pretty printed current date)
-s, --default-sizes <type> Module sizes to show in treemap by default.
Possible values: stat, parsed, gzip (default: parsed)
-O, --no-open Don't open report in default browser automatically.
-e, --exclude <regexp> Assets that should be excluded from the report.
Can be specified multiple times.
-l, --log-level <level> Log level.
Possible values: debug, info, warn, error, silent (default: info)
-h, --help output usage information
Size definitions
webpack-bundle-analyzer reports three values for sizes. defaultSizes
can be used to control which of these is shown by default. The different reported sizes are:
stat
This is the "input" size of your files, before any transformations like minification.
It is called "stat size" because it's obtained from Webpack's stats object.
parsed
This is the "output" size of your files. If you're using a Webpack plugin such as Uglify, then this value will reflect the minified size of your code.
gzip
This is the size of running the parsed bundles/modules through gzip compression.
Selecting Which Chunks to Display
When opened, the report displays all of the Webpack chunks for your project. It's possible to filter to a more specific list of chunks by using the sidebar or the chunk context menu.
Sidebar
The Sidebar Menu can be opened by clicking the >
button at the top left of the report. You can select or deselect chunks to display under the "Show chunks" heading there.
Chunk Context Menu
The Chunk Context Menu can be opened by right-clicking or Ctrl
-clicking on a specific chunk in the report. It provides the following options:
- Hide chunk: Hides the selected chunk
- Hide all other chunks: Hides all chunks besides the selected one
- Show all chunks: Un-hides any hidden chunks, returning the report to its initial, unfiltered view
Troubleshooting
I don't see gzip
or parsed
sizes, it only shows stat
size
It happens when webpack-bundle-analyzer
analyzes files that don't actually exist in your file system, for example when you work with webpack-dev-server
that keeps all the files in RAM. If you use webpack-bundle-analyzer
as a plugin you won't get any errors, however if you run it via CLI you get the error message in terminal:
Error parsing bundle asset "your_bundle_name.bundle.js": no such file
No bundles were parsed. Analyzer will show only original module sizes from stats file.
To get more information about it you can read issue #147.
Other tools
- Statoscope - Webpack bundle analyzing tool to find out why a certain module was bundled (and more features, including interactive treemap)
Maintainers
Yuriy Grunin |
Vesa Laakso |
Contributing
Check out CONTRIBUTING.md for instructions on contributing :tada:
Top Related Projects
A bundler for javascript and friends. Packs many modules into a few bundled assets. Code Splitting allows for loading parts of the application on demand. Through "loaders", modules can be CommonJs, AMD, ES6 modules, CSS, Images, JSON, Coffeescript, LESS, ... and your custom stuff.
The zero configuration build tool for the web. 📦🚀
Next-generation ES module bundler
An extremely fast bundler for the web
Build system optimized for JavaScript and TypeScript, written in Rust
Next generation frontend tooling. It's fast!
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Introducing Visual Copilot: A new AI model to turn Figma designs to high quality code using your components.
Try Visual Copilot