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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 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 config file

If for some reason you want to use different config 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.

webpack.config.js

const path = require('path');

module.exports = {
  
  // Chosen mode tells webpack to use its built-in optimizations accordingly.
  
  // defaults to ./src
  // Here the application starts executing
  // and webpack starts bundling
  
    // options related to how webpack emits results
    path: path.resolve(__dirname, "dist"), // string
    // the target directory for all output files
    // must be an absolute path (use the Node.js path module)
    
    // the filename template for entry chunks
    
    // the url to the output directory resolved relative to the HTML page
    library: "MyLibrary", // string,
    // the name of the exported library
    
    // the type of the exported library
    
    
  },
  module: {
    // configuration regarding modules
    rules: [
      // rules for modules (configure loaders, parser options, etc.)
      {
        test: /.jsx?$/,
        include: [
          path.resolve(__dirname, "app")
        ],
        exclude: [
          path.resolve(__dirname, "app/demo-files")
        ],
        // these are matching conditions, each accepting a regular expression or string
        // test and include have the same behavior, both must be matched
        // exclude must not be matched (takes preferrence over test and include)
        // Best practices:
        // - Use RegExp only in test and for filename matching
        // - Use arrays of absolute paths in include and exclude
        // - Try to avoid exclude and prefer include
        issuer: { test, include, exclude },
        // conditions for the issuer (the origin of the import)
        enforce: "pre",
        enforce: "post",
        // flags to apply these rules, even if they are overridden (advanced option)
        loader: "babel-loader",
        // the loader which should be applied, it'll be resolved relative to the context
        // -loader suffix is no longer optional in webpack2 for clarity reasons
        // see webpack 1 upgrade guide
        options: {
          presets: ["es2015"]
        },
        // options for the loader
      },
      {
        test: /.html$/,
        use: [
          // apply multiple loaders and options
          "htmllint-loader",
          {
            loader: "html-loader",
            options: {
              / ... /
            }
          }
        ]
      },
      { oneOf: [ / rules / ] },
      // only use one of these nested rules
      { rules: [ / rules / ] },
      // use all of these nested rules (combine with conditions to be useful)
      { resource: { and: [ / conditions / ] } },
      // matches only if all conditions are matched
      { resource: { or: [ / conditions / ] } },
      { resource: [ / conditions / ] },
      // matches if any condition is matched (default for arrays)
      { resource: { not: / condition / } }
      // matches if the condition is not matched
    ],
    
  },
  resolve: {
    // options for resolving module requests
    // (does not apply to resolving to loaders)
    modules: [
      "node_modules",
      path.resolve(__dirname, "app")
    ],
    // directories where to look for modules
    extensions: [".js", ".json", ".jsx", ".css"],
    // extensions that are used
    alias: {
      // a list of module name aliases
      "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
      // modules aliases are imported relative to the current context
    },
    
    
  },
  performance: {
    
    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');
    }
  },
  
  // 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
  
  // the environment in which the bundle should run
  // changes chunk loading behavior and available modules
  
  // Don't follow/bundle these modules, but request them at runtime from the environment
  serve: { //object
    port: 1337,
    content: './dist',
    // ...
  },
  // lets you provide options for webpack-serve
  
  // lets you precisely control what bundle information gets displayed
  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
    // ...
  },
  plugins: [
    // ...
  ],
  // list of additional plugins
  

Want to rapidly generate webpack configuration file for your project requirements with few clicks away.

Generate Custom Webpack Configuration is an interactive portal you can play around by selecting custom webpack configuration options tailored for your frontend project. It automatically generates a minimal webpack configuration based on your selection of loaders/plugins, etc.

Visual tool for creating webpack configs is an online configuration tool for creating webpack config where you can select any combination of features you need. It also generates a full example project based on your webpack configs.