web-extension-starter/webpack.config.js

const path = require('path');
const webpack = require('webpack');
const ZipPlugin = require('zip-webpack-plugin');
const TerserPlugin = require('terser-webpack-plugin');
const CopyWebpackPlugin = require('copy-webpack-plugin');
const HtmlWebpackPlugin = require('html-webpack-plugin');
const { CleanWebpackPlugin } = require('clean-webpack-plugin');
const ExtensionReloader = require('webpack-extension-reloader');
const MiniCssExtractPlugin = require('mini-css-extract-plugin');
const WextManifestWebpackPlugin = require('wext-manifest-webpack-plugin');
const ForkTsCheckerWebpackPlugin = require('fork-ts-checker-webpack-plugin');
const OptimizeCSSAssetsPlugin = require('optimize-css-assets-webpack-plugin');

const viewsPath = path.join(__dirname, 'views');
const sourcePath = path.join(__dirname, 'src');
const destPath = path.join(__dirname, 'extension');
const nodeEnv = process.env.NODE_ENV || 'development';
const targetBrowser = process.env.TARGET_BROWSER;

const extensionReloaderPlugin =
    nodeEnv === 'development'
        ? new ExtensionReloader({
              port: 9090,
              reloadPage: true,
              entries: {
                  // TODO: reload manifest on update
                  contentScript: 'contentScript',
                  background: 'background',
                  extensionPage: ['popup', 'options'],
              },
          })
        : () => {
              this.apply = () => {};
          };

const getExtensionFileType = (browser) => {
    if (browser === 'opera') {
        return 'crx';
    }

    if (browser === 'firefox') {
        return 'xpi';
    }

    return 'zip';
};

module.exports = {
    mode: nodeEnv,

    entry: {
        manifest: path.join(sourcePath, 'manifest.json'),
        background: path.join(sourcePath, 'Background', 'index.ts'),
        contentScript: path.join(sourcePath, 'ContentScript', 'index.ts'),
        popup: path.join(sourcePath, 'Popup', 'index.tsx'),
        options: path.join(sourcePath, 'Options', 'index.tsx'),
    },

    output: {
        path: path.join(destPath, targetBrowser),
        filename: 'js/[name].bundle.js',
    },

    resolve: {
        extensions: ['.ts', '.tsx', '.js', '.json'],
        alias: {
            'webextension-polyfill-ts': path.resolve(path.join(__dirname, 'node_modules', 'webextension-polyfill-ts')),
        },
    },

    module: {
        rules: [
            {
                type: 'javascript/auto', // prevent webpack handling json with its own loaders,
                test: /manifest\.json$/,
                use: {
                    loader: 'wext-manifest-loader',
                    options: {
                        usePackageJSONVersion: true, // set to false to not use package.json version for manifest
                    },
                },
                exclude: /node_modules/,
            },
            {
                test: /\.(js|ts)x?$/,
                loader: 'babel-loader',
                exclude: /node_modules/,
            },
            {
                test: /\.(sa|sc|c)ss$/,
                use: [
                    {
                        loader: MiniCssExtractPlugin.loader, // It creates a CSS file per JS file which contains CSS
                    },
                    {
                        loader: 'css-loader', // Takes the CSS files and returns the CSS with imports and url(...) for Webpack
                        options: {
                            sourceMap: true,
                        },
                    },
                    {
                        loader: 'postcss-loader', // For autoprefixer
                        options: {
                            ident: 'postcss',
                            // eslint-disable-next-line global-require, @typescript-eslint/no-var-requires
                            plugins: [require('autoprefixer')()],
                        },
                    },
                    'resolve-url-loader', // Rewrites relative paths in url() statements
                    'sass-loader', // Takes the Sass/SCSS file and compiles to the CSS
                ],
            },
        ],
    },

    plugins: [
        // Plugin to not generate js bundle for manifest entry
        new WextManifestWebpackPlugin(),
        new ForkTsCheckerWebpackPlugin(),
        // environmental variables
        new webpack.EnvironmentPlugin(['NODE_ENV', 'TARGET_BROWSER']),
        // delete previous build files
        new CleanWebpackPlugin({
            cleanOnceBeforeBuildPatterns: [
                path.join(process.cwd(), `extension/${targetBrowser}`),
                path.join(process.cwd(), `extension/${targetBrowser}.${getExtensionFileType(targetBrowser)}`),
            ],
            cleanStaleWebpackAssets: false,
            verbose: true,
        }),
        new HtmlWebpackPlugin({
            template: path.join(viewsPath, 'popup.html'),
            inject: 'body',
            chunks: ['popup'],
            filename: 'popup.html',
        }),
        new HtmlWebpackPlugin({
            template: path.join(viewsPath, 'options.html'),
            inject: 'body',
            chunks: ['options'],
            filename: 'options.html',
        }),
        // write css file(s) to build folder
        new MiniCssExtractPlugin({ filename: 'css/[name].css' }),
        // copy static assets
        new CopyWebpackPlugin([{ from: 'src/assets', to: 'assets' }]),
        // plugin to enable browser reloading in development mode
        extensionReloaderPlugin,
    ],

    optimization: {
        minimizer: [
            new TerserPlugin({
                cache: true,
                parallel: true,
                terserOptions: {
                    output: {
                        comments: false,
                    },
                },
                extractComments: false,
            }),
            new OptimizeCSSAssetsPlugin({
                cssProcessorPluginOptions: {
                    preset: ['default', { discardComments: { removeAll: true } }],
                },
            }),
            new ZipPlugin({
                path: destPath,
                extension: `${getExtensionFileType(targetBrowser)}`,
                filename: `${targetBrowser}`,
            }),
        ],
    },
};