webpack-dev-server

What is webpack-dev-server?

webpack-dev-server is a development server that provides live reloading. It is intended to be used with webpack, a module bundler. It uses webpack's watch mode and, when changes are detected, it recompiles the bundle and notifies the client to reload the page.

What are webpack-dev-server's main functionalities?

Live Reloading

Automatically reloads the page when files are changed. The 'hot' option enables Hot Module Replacement without page refresh as fallback in case of build failures.

module.exports = {
  devServer: {
    contentBase: './dist',
    hot: true
  }
};

Custom Middleware

Allows developers to add custom routes before the server starts. Useful for mocking an API or other custom server logic.

module.exports = {
  devServer: {
    before: function(app, server) {
      app.get('/some/path', function(req, res) {
        res.json({ custom: 'response' });
      });
    }
  }
};

Proxying API Requests

Redirects API calls to another server. This is useful when you have a separate API backend development server and you want to send API requests on the same domain.

module.exports = {
  devServer: {
    proxy: {
      '/api': 'http://localhost:3000'
    }
  }
};

HTTPS Support

Allows serving the webpack application over HTTPS. This is useful for testing applications that require secure connections.

module.exports = {
  devServer: {
    https: true
  }
};

Other packages similar to webpack-dev-server

browser-sync

BrowserSync is an automation tool that makes web development faster. It synchronizes file changes and interactions across multiple devices. It's similar to webpack-dev-server but works across multiple browsers and devices.

lite-server

Lite-server is a lightweight development server that serves a web app, opens it in the browser, and refreshes the browser on file changes. It is built on top of BrowserSync and provides fewer configuration options compared to webpack-dev-server.

serve

Serve is a static server that lets you serve static files quickly. It is simpler than webpack-dev-server and does not have built-in support for live reloading or module bundling.

http-server

http-server is a simple, zero-configuration command-line HTTP server. It is powerful and has the ability to serve static files, but lacks the advanced features of webpack-dev-server like live reloading and module hot replacement.

README

webpack-dev-server

Use webpack with a development server that provides live reloading. This should be used for development only.

It uses webpack-dev-middleware under the hood, which provides fast in-memory access to the webpack assets.

Table of Contents

• Getting Started
• Usage
  • With the CLI
  • With NPM Scripts
  • The Result
• Browser Support
• Support
• Contributing
• Attribution
• License

Getting Started

First things first, install the module:

npm install webpack-dev-server --save-dev

Note: While you can install and run webpack-dev-server globally, we recommend installing it locally. webpack-dev-server will always use a local installation over a global one.

Usage

There are two main, recommended methods of using the module:

With the CLI

The easiest way to use it is with the webpack CLI. In the directory where your webpack.config.js is, run:

node_modules/.bin/webpack serve

Following options are available with webpack serve:

Usage: webpack serve|s [entries...] [options]

Options:
  -c, --config <value...>    Provide path to a webpack configuration file e.g. ./webpack.config.js.
  --config-name <value...>   Name of the configuration to use.
  -m, --merge                Merge two or more configurations using 'webpack-merge'.
  --env <value...>           Environment passed to the configuration when it is a function.
  --node-env <value>         Sets process.env.NODE_ENV to the specified value.
  --progress [value]         Print compilation progress during build.
  -j, --json [value]         Prints result as JSON or store it in a file.
  -d, --devtool <value>      Determine source maps to use.
  --no-devtool               Do not generate source maps.
  --entry <value...>         The entry point(s) of your application e.g. ./src/main.js.
  --mode <value>             Defines the mode to pass to webpack.
  --name <value>             Name of the configuration. Used when loading multiple configurations.
  -o, --output-path <value>  Output location of the file generated by webpack e.g. ./dist/.
  --stats [value]            It instructs webpack on how to treat the stats e.g. verbose.
  --no-stats                 Disable stats output.
  -t, --target <value...>    Sets the build target e.g. node.
  --no-target                Negative 'target' option.
  --watch-options-stdin      Stop watching when stdin stream has ended.
  --no-watch-options-stdin   Do not stop watching when stdin stream has ended.
  --host <value>             The hostname/ip address the server will bind to.
  --port <value>             The port server will listen to.
  --static [value...]        A directory to serve static content from.
  --no-static                Negative 'static' option.
  --live-reload              Enables live reloading on changing files.
  --no-live-reload           Disables live reloading on changing files.
  --https                    Use HTTPS protocol.
  --no-https                 Do not use HTTPS protocol.
  --http2                    Use HTTP/2, must be used with HTTPS.
  --no-http2                 Do not use HTTP/2.
  --bonjour                  Broadcasts the server via ZeroConf networking on start.
  --no-bonjour               Do not broadcast the server via ZeroConf networking on start.
  --client-progress          Print compilation progress in percentage in the browser.
  --no-client-progress       Do not print compilation progress in percentage in the browser.
  --client-overlay           Show a full-screen overlay in the browser when there are compiler errors or warnings.
  --no-client-overlay        Do not show a full-screen overlay in the browser when there are compiler errors or warnings.
  --setup-exit-signals       Close and exit the process on SIGINT and SIGTERM.
  --no-setup-exit-signals    Do not close and exit the process on SIGNIT and SIGTERM.
  --open [value...]          Open the default browser.
  --no-open                  Do not open the default browser.
  --open-app <value>         Open specified browser.
  --open-target [value...]   Open specified route in browser.
  --no-open-target           Do not open specified route in browser.
  --client-logging <value>   Log level in the browser (none, error, warn, info, log, verbose).
  --history-api-fallback     Fallback to /index.html for Single Page Applications.
  --no-history-api-fallback  Do not fallback to /index.html for Single Page Applications.
  --compress                 Enable gzip compression.
  --no-compress              Disable gzip compression.
  --public <value>           The public hostname/ip address of the server.
  --firewall [value...]      Enable firewall or set hosts that are allowed to access the dev server.
  --no-firewall              Disable firewall.
  --watch-files <value...>   Watch static files for file changes.

Global options:
  --color                    Enable colors on console.
  --no-color                 Disable colors on console.
  -v, --version              Output the version number of 'webpack', 'webpack-cli' and 'webpack-dev-server' and commands.
  -h, --help [verbose]       Display help for commands and options.

Note: For more information on above options explore this link.

With NPM Scripts

NPM package.json scripts are a convenient and useful means to run locally installed binaries without having to be concerned about their full paths. Simply define a script as such:

{
  "scripts": {
    "serve": "webpack serve"
  }
}

And run the following in your terminal/console:

npm run start:dev

NPM will automagically reference the binary in node_modules for you, and execute the file or command.

The Result

Either method will start a server instance and begin listening for connections from localhost on port 8080.

webpack-dev-server is configured by default to support live-reload of files as you edit your assets while the server is running.

See the documentation for more use cases and options.

Browser Support

While webpack-dev-server transpiles the client (browser) scripts to an ES5 state, the project only officially supports the last two versions of major browsers. We simply don't have the resources to support every whacky browser out there.

If you find a bug with an obscure / old browser, we would actively welcome a Pull Request to resolve the bug.

Support

We do our best to keep Issues in the repository focused on bugs, features, and needed modifications to the code for the module. Because of that, we ask users with general support, "how-to", or "why isn't this working" questions to try one of the other support channels that are available.

Your first-stop-shop for support for webpack-dev-server should be the excellent documentation for the module. If you see an opportunity for improvement of those docs, please head over to the webpack.js.org repo and open a pull request.

From there, we encourage users to visit the webpack Gitter chat and talk to the fine folks there. If your quest for answers comes up dry in chat, head over to StackOverflow and do a quick search or open a new question. Remember; It's always much easier to answer questions that include your webpack.config.js and relevant files!

If you're twitter-savvy you can tweet #webpack with your question and someone should be able to reach out and lend a hand.

If you have discovered a :bug:, have a feature suggestion, or would like to see a modification, please feel free to create an issue on Github. Note: The issue template isn't optional, so please be sure not to remove it, and please fill it out completely.

Contributing

We welcome your contributions! Please have a read of CONTRIBUTING.md for more information on how to get involved.

Attribution

This project is heavily inspired by peerigon/nof5.

License

MIT

Changelog

4.0.0-beta.2 (2021-04-06)

⚠ BREAKING CHANGES

• the openPage option and the --open-page CLI option were removed in favor { open: ['/my-page', '/my-other-page/'] } for Node.js API and --open-target [URL] (without [URL] dev server will open a browser using the host option value) and --open-app <browser> for CLI
• the useLocalIp option was removed in favor { host: 'local-ip' }, alternative you can provide values: local-ipv4 for IPv4 and local-ipv6 for IPv6
• stdin option was removed in favor --watch-options-stdin
• injectClient and injectHot was removed in favor client.needClientEntry and client.needHotEntry

Features

• added the watchFiles option, now you can reload server on file changes, for example { watchFiles: ['src/**/*.php', 'public/**/*'] } (#3136) (d73213a)
• added more CLI options, please run webpack server --help (#3148) (03a2b27)
• enable overlay by default (#3108) (5e05e48)
• you can specify multiple targets and browsers for the open option, i.e. { open: { target: ['/my-page', '/my-other-page'], app: ['google-chrome', '--incognito'] } } (e3c2683)

Bug Fixes

• /webpack-dev-server url shows list of files (#3101) (b3374c3)

• dev server client compatibility with IE11/IE10/IE9 (#3129) (1e3e656)

  • For IE11/IE10 you need polyfill fetch() and Promise, example:

  module.exports = {
    entry: {
      entry: [
        'whatwg-fetch', 
        'core-js/features/promise', 
        './entry.js'
      ],
    },
  };
  

  • For IE9 you need polyfill fetch() and Promise and use sockjs for communications (because WebSocket is not supported), example:

  module.exports = {
    entry: {
      entry: [
        'whatwg-fetch', 
        'core-js/features/promise', 
        './entry.js'
      ],
    },
    devServer: {
      transportMode: 'sockjs',
    },
  };
  

  IE8 is not supported

• hostname resolving (#3128) (cd39491)

• improve CLI options (#3151) (09fa827)

• output description on invalid options (#3154) (2e02978)

• prefer to open the host option (#3115) (7e525eb)

• reduce number of dependencies