Chrome Extension (MV3) Boilerplate with React 18 and Webpack 5

Announcements

• Recently updated from React 17 to 18!
• This boilerplate adopts Manifest V3!
  • For V2 users, please check out the manifest-v2 branch, or use version 3.x.
  • Check out the Manifest V3 Migration Guide.
• Recently added devtools Support! Thanks GeekaholicLin!
• Recently updated from Webpack Dev Server 3.x to 4.x and Webpack 4 to 5!
• Recently added TypeScript Support!

Features

This is a basic Chrome Extensions boilerplate to help you write modular and modern Javascript code, load CSS easily and automatic reload the browser on code changes.

This boilerplate is updated with:

• Chrome Extension Manifest V3
• React 18
• Webpack 5
• Webpack Dev Server 4
• React Refresh
• react-refresh-webpack-plugin
• eslint-config-react-app
• Prettier
• TypeScript

This boilerplate is heavily inspired by and adapted from https://github.com/samuelsimoes/chrome-extension-webpack-boilerplate, with additional support for React 18 features, Webpack 5, and Webpack Dev Server 4.

Please open up an issue to nudge me to keep the npm packages up-to-date. FYI, it takes time to make different packages with different versions work together nicely.

Installing and Running

Procedures:

1. Check if your Node.js version is >= 18.
2. Clone this repository.
3. Change the package’s name, description, and repository fields in package.json.
4. Change the name of your extension on src/manifest.json.
5. Run npm install to install the dependencies.
6. Run npm start
7. Load your extension on Chrome following:
   1. Access chrome://extensions/
   2. Check Developer mode
   3. Click on Load unpacked extension
   4. Select the build folder.
8. Happy hacking.

Structure

All your extension’s code must be placed in the src folder.

The boilerplate is already prepared to have a popup, an options page, a background page, and a new tab page (which replaces the new tab page of your browser). But feel free to customize these.

TypeScript

This boilerplate now supports TypeScript! The Options Page is implemented using TypeScript. Please refer to src/pages/Options/ for example usages.

Webpack auto-reload and HRM

To make your workflow much more efficient this boilerplate uses the webpack server to development (started with npm start) with auto reload feature that reloads the browser automatically every time that you save some file in your editor.

You can run the dev mode on other port if you want. Just specify the env var port like this:

$ PORT=6002 npm run start

Content Scripts

Although this boilerplate uses the webpack dev server, it’s also prepared to write all your bundles files on the disk at every code change, so you can point, on your extension manifest, to your bundles that you want to use as content scripts, but you need to exclude these entry points from hot reloading (why?). To do so you need to expose which entry points are content scripts on the webpack.config.js using the chromeExtensionBoilerplate -> notHotReload config. Look the example below.

Let’s say that you want use the myContentScript entry point as content script, so on your webpack.config.js you will configure the entry point and exclude it from hot reloading, like this:

{
  …
  entry: {
    myContentScript: "./src/js/myContentScript.js"
  },
  chromeExtensionBoilerplate: {
    notHotReload: ["myContentScript"]
  }
  …
}

and on your src/manifest.json:

{
  "content_scripts": [
    {
      "matches": ["https://www.google.com/*"],
      "js": ["myContentScript.bundle.js"]
    }
  ]
}

Intelligent Code Completion

Thanks to @hudidit’s kind suggestions, this boilerplate supports chrome-specific intelligent code completion using @types/chrome.

Packing

After the development of your extension run the command

$ NODE_ENV=production npm run build

Now, the content of build folder will be the extension ready to be submitted to the Chrome Web Store. Just take a look at the official guide to more infos about publishing.

Secrets

If you are developing an extension that talks with some API you probably are using different keys for testing and production. Is a good practice you not commit your secret keys and expose to anyone that have access to the repository.

To this task this boilerplate import the file ./secrets.<THE-NODE_ENV>.js on your modules through the module named as secrets, so you can do things like this:

./secrets.development.js

export default { key: '123' };

./src/popup.js

import secrets from 'secrets';
ApiCall({ key: secrets.key });

👉 The files with name secrets.*.js already are ignored on the repository.

Resources:

• Webpack documentation
• Chrome Extension documentation

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Michael Xieyang Liu | Website