Configuration
Out of the box, webpack won't require you to use a configuration file. However, it will assume the entry point of your project is src/index.js and will output the result in dist/main.js minified and optimized for production.
Usually your projects will need to extend this functionality, for this you can create a webpack.config.js file in the root folder and webpack will automatically use it.
All the available configuration options are specified below.
New to webpack? Check out our guide to some of webpack's core concepts to get started!
Use different configuration file
If for some reason you want to use different configuration file depending on certain situations you can change this via command line by using the --config flag.
package.json
"scripts": {
"build": "webpack --config prod.config.js"
}Options
Click on the name of each option in the configuration code below to jump to the detailed documentation. Also note that the items with arrows can be expanded to show more examples and, in some cases, more advanced configuration.
Notice that throughout the configuration we use Node's built-in path module and prefix it with the __dirname global. This prevents file path issues between operating systems and allows relative paths to work as expected. See this section for more info on POSIX vs. Windows paths.
Notice that many array configurations allow to reference the default value via
"...".
webpack.config.js
const path = require('path');
module.exports = {
mode: "production", // "production" | "development" | "none"
// Chosen mode tells webpack to use its built-in optimizations accordingly.
entry: "./app/entry", // string | object | array
// defaults to ./src
// Here the application starts executing
// and webpack starts bundling
output: {
// options related to how webpack emits results
path:path.resolve(__dirname, "dist"), // string (default)
// the target directory for all output files
// must be an absolute path (use the Node.js path module)
filename: "[name].js", // string (default)
// the filename template for entry chunks
publicPath: "/assets/", // string
// the url to the output directory resolved relative to the HTML page
library: { // There is also an old syntax for this available (click to show)
type: "umd", // universal module definition
// the type of the exported library
name: "MyLibrary", // string | string[]
// the name of the exported library
/* Advanced output.library configuration (click to show) */
},
uniqueName: "my-application", // (defaults to package.json "name")
// unique name for this build to avoid conflicts with other builds in the same HTML
name: "my-config",
// name of the configuration, shown in output
/* Advanced output configuration (click to show) */
/* Expert output configuration 1 (on own risk) */
/* Expert output configuration 2 (on own risk) */
},
module: {
// configuration regarding modules
rules: [
// rules for modules (configure loaders, parser options, etc.)
{
// Conditions:
test: /\\.jsx?$/,
include: [
path.resolve(__dirname, "app")
],
exclude: [
path.resolve(__dirname, "app/demo-files")
],
// these are matching conditions, each accepting a regular expression or string
// test and include have the same behavior, both must be matched
// exclude must not be matched (takes preferrence over test and include)
// Best practices:
// - Use RegExp only in test and for filename matching
// - Use arrays of absolute paths in include and exclude to match the full path
// - Try to avoid exclude and prefer include
// Each condition can also receive an object with "and", "or" or "not" properties
// which are an array of conditions.
issuer: /\\.css$/,
issuer: path.resolve(__dirname, "app"),
issuer: { and: [ /\\.css$/, path.resolve(__dirname, "app") ] },
issuer: { or: [ /\\.css$/, path.resolve(__dirname, "app") ] },
issuer: { not: [ /\\.css$/ ] },
issuer: [ /\\.css$/, path.resolve(__dirname, "app") ], // like "or"
// conditions for the issuer (the origin of the import)
/* Advanced conditions (click to show) */
// Actions:
loader: "babel-loader",
// the loader which should be applied, it'll be resolved relative to the context
options: {
presets: ["es2015"]
},
// options for the loader
use: [
// apply multiple loaders and options instead
"htmllint-loader",
{
loader: "html-loader",
options: {
// ...
}
}
]
type: "javascript/auto",
// specifies the module type
/* Advanced actions (click to show) */
},
{
oneOf: [
// ... (rules)
]
// only use one of these nested rules
},
{
// ... (conditions)
rules: [
// ... (rules)
]
// use all of these nested rules (combine with conditions to be useful)
},
],
/* Advanced module configuration (click to show) */
},
resolve: {
// options for resolving module requests
// (does not apply to resolving of loaders)
modules: ["node_modules",path.resolve(__dirname, "app")],
// directories where to look for modules (in order)
extensions: [".js", ".json", ".jsx", ".css"],
// extensions that are used
alias: {
// a list of module name aliases
// aliases are imported relative to the current context
"module": "new-module",
// alias "module" -> "new-module" and "module/path/file" -> "new-module/path/file"
"only-module$": "new-module",
// alias "only-module" -> "new-module", but not "only-module/path/file" -> "new-module/path/file"
"module": path.resolve(__dirname, "app/third/module.js"),
// alias "module" -> "./app/third/module.js" and "module/file" results in error
"module": path.resolve(__dirname, "app/third"),
// alias "module" -> "./app/third" and "module/file" -> "./app/third/file"
[path.resolve(__dirname, "app/module.js")]: path.resolve(__dirname, "app/alternative-module.js"),
// alias "./app/module.js" -> "./app/alternative-module.js"
},
/* Alternative alias syntax (click to show) */
/* Advanced resolve configuration (click to show) */
/* Expert resolve configuration (click to show) */
},
performance: {
hints: "warning", // enum
maxAssetSize: 200000, // int (in bytes),
maxEntrypointSize: 400000, // int (in bytes)
assetFilter: function(assetFilename) {
// Function predicate that provides asset filenames
return assetFilename.endsWith('.css') || assetFilename.endsWith('.js');
}
},
devtool: "source-map", // enum
// enhance debugging by adding meta info for the browser devtools
// source-map most detailed at the expense of build speed.
context: __dirname, // string (absolute path!)
// the home directory for webpack
// the entry and module.rules.loader option
// is resolved relative to this directory
target: "web", // enum
// the environment in which the bundle should run
// changes chunk loading behavior, available external modules
// and generated code style
externals: ["react", /^@angular/],
// Don't follow/bundle these modules, but request them at runtime from the environment
externalsType: "var", // (defaults to output.library.type)
// Type of externals, when not specified inline in externals
externalsPresets: { /* ... */ },
// presets of externals
ignoreWarnings: [/warning/],
stats: "errors-only",
stats: {
// lets you precisely control what bundle information gets displayed
preset: "errors-only",
// A stats preset
/* Advanced global settings (click to show) */
env: true,
// include value of --env in the output
outputPath: true,
// include absolute output path in the output
publicPath: true,
// include public path in the output
assets: true,
// show list of assets in output
/* Advanced assets settings (click to show) */
entrypoints: true,
// show entrypoints list
chunkGroups: true,
// show named chunk group list
/* Advanced chunk group settings (click to show) */
chunks: true,
// show list of chunks in output
/* Advanced chunk group settings (click to show) */
modules: true,
// show list of modules in output
/* Advanced module settings (click to show) */
/* Expert module settings (click to show) */
/* Advanced optimization settings (click to show) */
children: true
// show stats for child compilations
logging: true,
// show logging in output
loggingDebug: /webpack/,
// show debug type logging for some loggers
loggingTrace: true,
// show stack traces for warnings and errors in logging output
warnings: true
// show warnings
errors: true,
// show errors
errorDetails: true,
// show details for errors
errorStack: true,
// show internal stack trace for errors
moduleTrace: true,
// show module trace for errors
// (why was causing module referenced)
builtAt: true,
// show timestamp in summary
errorsCount: true,
// show errors count in summary
warningsCount: true,
// show warnings count in summary
timings: true,
// show build timing in summary
version: true,
// show webpack version in summary
hash: true,
// show build hash in summary
},
devServer: {
proxy: { // proxy URLs to backend development server
'/api': 'http://localhost:3000'
},
contentBase: path.join(__dirname, 'public'), // boolean | string | array, static file location
compress: true, // enable gzip compression
historyApiFallback: true, // true for index.html upon 404, object for multiple paths
hot: true, // hot module replacement. Depends on HotModuleReplacementPlugin
https: false, // true for self-signed, object for cert authority
noInfo: true, // only errors & warns on hot reload
// ...
},
experiments: {
asyncWebAssembly: true,
// WebAssembly as async module (Proposal)
syncWebAssembly: true,
// WebAssembly as sync module (deprecated)
outputModule: true,
// Allow to output ESM
topLevelAwait: true,
// Allow to use await on module evaluation (Proposal)
}
plugins: [
// ...
],
// list of additional plugins
optimization: {
chunkIds: "size",
// method of generating ids for chunks
moduleIds: "size",
// method of generating ids for modules
mangleExports: "size",
// rename export names to shorter names
minimize: true,
// minimize the output files
minimizer: [new CssMinimizer(), "..."],
// minimizers to use for the output files
/* Advanced optimizations (click to show) */
splitChunks: {
cacheGroups: {
"my-name": {
// define groups of modules with specific
// caching behavior
test: /\\.sass$/,
type: "css/mini-extract",
/* Advanced selectors (click to show) */
/* Advanced effects (click to show) */
}
},
fallbackCacheGroup: { /* Advanced (click to show) */ }
/* Advanced selectors (click to show) */
/* Advanced effects (click to show) */
/* Expert settings (click to show) */
}
},
/* Advanced configuration (click to show) */
/* Advanced caching configuration (click to show) */
/* Advanced build configuration (click to show) */webpack applies configuration defaults after plugins defaults are applied.
Use webpack-cli's init command to rapidly generate webpack configuration file for your project requirements, it will ask you a couple of questions before creating a configuration file.
npx webpack-cli initnpx might prompt you to install @webpack-cli/init if it is not yet installed in the project or globally. You might also get additional packages installed to your project depending on the choices you've made during the configuration generation.
npx webpack-cli init
βΉ INFO For more information and a detailed description of each question, have a look at https://github.com/webpack/webpack-cli/blob/master/INIT.md
βΉ INFO Alternatively, run `webpack(-cli) --help` for usage info.
? Will your application have multiple bundles? No
? Which module will be the first to enter the application? [default: ./src/index]
? Which folder will your generated bundles be in? [default: dist]:
? Will you be using ES2015? Yes
? Will you use one of the below CSS solutions? No
+ babel-plugin-syntax-dynamic-import@6.18.0
+ uglifyjs-webpack-plugin@2.0.1
+ webpack-cli@3.2.3
+ @babel/core@7.2.2
+ babel-loader@8.0.4
+ @babel/preset-env@7.1.0
+ webpack@4.29.3
added 124 packages from 39 contributors, updated 4 packages and audited 25221 packages in 7.463s
found 0 vulnerabilities
Congratulations! Your new webpack configuration file has been created!createapp.dev - create a webpack configuration in your browser is an online tool for creating custom webpack configuration. It allows you to select various features that will be combined and added to resulting configuration file. Also, it generates an example project based on provided webpack configuration that you can review in your browser and download.
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