How to configure Vite/React to build a Google Chrome (Web) Extension

This is how I set up Vite to meet my requirements for building a Web Extension for Google Chrome, since other Browsers also support Web Extensions with Manifest v3 it should also apply to Firefox, Edge and Safari.

Create a new project

I am going to use React for this extension, so the first step is to create a new React/Typescript project:

npm create vite@latest
? Project name: › my-web-extension
? Select a framework: › React
? Select a variant: › TypeScript
cd my-web-extension
npm i
git init
git add --all
git commit -m "blank vite react/typescript project"

Setup ESLint

For linting I am used to the create-react-app config, fortunately this is maintained in a dedicated package: https://www.npmjs.com/package/eslint-config-react-app

1. Install the required packages:

npm install --save-dev eslint-config-react-app eslint@^8.0.0

1. To configure ESLint create a .eslintrc.json file in the root of the project and add this configuration:

{
  "extends": "react-app"
}

Alternatively you can add your config to the eslintConfig field of package.json

If ESLint is integrated into your editor, you should already see that it complains about the target="_blank" links in src/App.tsx not having rel="noreferrer".

Commit your changes.

Add a Manifest and multiple entry points

To make your output get recognized as a Web Extension there has to be a Manifest file in the output folder.

Per default Vite will copy all content of the folder public to the output directory when building, so we just have to add the manifest file in there: public/manifest.json

As a starter we are just going to add an options page and a browser action to the extension:

{
    "manifest_version": 3,
    "name": "My Web Extension",
    "version": "0.0.1",
    "description": "A Web Extension created with Vite",
    "options_page": "options.html",
    "action": {
        "default_title": "View all available tests",
        "default_popup": "popup.html"
    }
}

As you might have noticed the two pages options.html and popup.html do not exist yet.

Vite supports multi-page apps with multiple .html entry points. To use this feature we have to create both files and specify them as entry points in vite.config.js:

import { resolve } from 'path'
import { defineConfig } from 'vite'
import react from '@vitejs/plugin-react'

// https://vitejs.dev/config/
export default defineConfig({
  plugins: [react()],
  build: {
    rollupOptions: {
      input: {
        main: resolve(__dirname, 'index.html'),
        popup: resolve(__dirname, 'popup.html'),
        options: resolve(__dirname, 'options.html'),
      },
    },
  },
})

For testing I just duplicated the original index.html twice and renamed it to popup.html and options.html respectively.

If your editor complains about missing types for path and __dirname this is because we did not yet install the types for node.

npm install --save @types/node

Build and run

That's it, time to run npm run build to build the extension. If you are using Google Chrome you can now load the extension in Settings/Extensions by clicking on "Load unpacked" and selecting the dist folder of this project.

Repository: https://github.com/receter/vite-minimal-web-extension

Happy coding!