webpack.config.js

var path = require("path");
var webpack = require("webpack");
var HtmlWebpackPlugin = require("html-webpack-plugin");
var TerserPlugin = require("terser-webpack-plugin");

module.exports = ({ googleAnalytics, longTermCaching } = {}, { mode } = {}) => ({
	entry: {
		web: "./app/entry.js"
	},
	cache: {
		type: "filesystem",
		buildDependencies: {
			config: [__filename]
		}
	},
	// Ported from the Grunt "webpack-dev-server:development" task, which merged
	// `devtool: "eval"` into the config for dev builds only.
	devtool: mode === "development" ? "eval" : false,
	devServer: {
		port: 8080,
		// `contentBase: "dist"` is deliberately not carried over. It existed to
		// serve the index.html that the Grunt "copy" task wrote into dist/; that
		// file is now generated by HtmlWebpackPlugin and served from memory, so
		// pointing the dev server at dist/ would only let a stale production
		// build shadow it. `keepAlive` was a Grunt task-runner concern.
		static: false
	},
	// Replaces the Grunt production task's `webpack.optimize.UglifyJsPlugin()`.
	// Only applied when `optimization.minimize` is on, which `--mode production`
	// enables and `--mode development` does not.
	optimization: {
		minimizer: [
			new TerserPlugin({
				parallel: true,
				// Keep third-party license banners out of the bundles but still
				// shipped, in a sidecar <chunk>.js.LICENSE.txt file.
				extractComments: true,
				terserOptions: {
					// webpack's built-in default minimizer uses two compress
					// passes; keep parity so making this explicit does not
					// regress output size.
					compress: { passes: 2 },
					format: { comments: false }
				}
			})
		]
	},
	output: {
		publicPath: "",
		filename: "[name].js",
		chunkFilename: longTermCaching ? "[contenthash].js" : undefined
	},
	module: {
		rules: [
			{ test: /\.pug$/, use: "pug-loader" },
			{ test: /\.css$/, use: ["style-loader", "css-loader"] },
			{ test: /\.png$/, type: "asset" }
		]
	},
	plugins: [
		new HtmlWebpackPlugin({
			template: "./app/index.html"
		}),
		googleAnalytics &&
			new webpack.DefinePlugin({
				GA_TRACKING_CODE: JSON.stringify("UA-46921629-1"),
				GA_TRACKING_CONFIG: JSON.stringify("webpack.github.io")
			})
	].filter(Boolean)
});