react-create-app项目解析一 webpack.config.js

此次isEnvProduction=true为例

bail	在第一个错误出现时抛出失败结果，而不是容忍它.开发环境设置为false，生产打包设置为true
devtool	是否生成，以及如何生成 source map
entry	打包入口文件 paths.appIndexJs为我们的入口文件目录 isEnvDevelopment && !shouldUseReactRefresh ? [webpackDevClientEntry,paths.appIndexJs,] : paths.appIndexJs 如果是开发环境，且shouldUseReactRefresh为false，那么就使用数组里面的配置，这个是react-create-app自定义的WebpackDevServer，默认情况它是被禁用的。
output	打包输出文件，下面单独分析。
optimization	下面单独分析。
resolve
resolveLoader
module
plugins
node
performance

output 配置代码

output: {
			// The build folder.
			path: isEnvProduction ? paths.appBuild : undefined,
			// Add /* filename */ comments to generated require()s in the output.
			pathinfo: isEnvDevelopment,
			// There will be one main bundle, and one file per asynchronous chunk.
			// In development, it does not produce real files.
			filename: isEnvProduction
				? "static/js/[name].[contenthash:8].js"
				: isEnvDevelopment && "static/js/bundle.js",
			// TODO: remove this when upgrading to webpack 5
			futureEmitAssets: true,
			// There are also additional JS chunk files if you use code splitting.
			chunkFilename: isEnvProduction
				? "static/js/[name].[contenthash:8].chunk.js"
				: isEnvDevelopment && "static/js/[name].chunk.js",
			// webpack uses `publicPath` to determine where the app is being served from.
			// It requires a trailing slash, or the file assets will get an incorrect path.
			// We inferred the "public path" (such as / or /my-project) from homepage.
			publicPath: paths.publicUrlOrPath,
			// Point sourcemap entries to original disk location (format as URL on Windows)
			devtoolModuleFilenameTemplate: isEnvProduction
				? (info) =>
						path
							.relative(paths.appSrc, info.absoluteResourcePath)
							.replace(/\\/g, "/")
				: isEnvDevelopment &&
				  ((info) =>
						path
							.resolve(info.absoluteResourcePath)
							.replace(/\\/g, "/")),
			// Prevents conflicts when multiple webpack runtimes (from different apps)
			// are used on the same page.
			jsonpFunction: `webpackJsonp${appPackageJson.name}`,
			// this defaults to 'window', but by setting it to 'this' then
			// module chunks which are built will work in web workers as well.
			globalObject: "this",
		},

path: isEnvProduction ? paths.appBuild : undefined,	打包输入文件目录
pathinfo: isEnvDevelopment,	告知 webpack 在 bundle 中引入「所包含模块信息」的相关注释。此选项在 development 模式时的默认值为 true，而在 production 模式时的默认值为 false。当值为 'verbose' 时，会显示更多信息，如 export，运行时依赖以及 bailouts。
filename: isEnvProduction ? "static/js/[name].[contenthash:8].js" : isEnvDevelopment && "static/js/bundle.js",	打包生成文件名称， [contenthash:8] hash前8位。
chunkFilename: isEnvProduction ? "static/js/[name].[contenthash:8].chunk.js" : isEnvDevelopment && "static/js/[name].chunk.js",	chunkFile文件名称
publicPath: paths.publicUrlOrPath	指定在浏览器中所引用的「此输出目录对应的公开 URL」。相对 URL(relative URL) 会被相对于 HTML 页面（或 <base> 标签）解析。相对于服务的 URL(Server-relative URL)，相对于协议的 URL(protocol-relative URL) 或绝对 URL(absolute URL) 也可是可能用到的，或者有时必须用到，例如：当将资源托管到 CDN 时
devtoolModuleFilenameTemplate: isEnvProduction ? (info) => path .relative(paths.appSrc, info.absoluteResourcePath) .replace(/\\/g, "/") : isEnvDevelopment && ((info) => path .resolve(info.absoluteResourcePath) .replace(/\\/g, "/")),	此选项仅在 「devtool 使用了需要模块名称的选项」时使用。 自定义每个 source map 的 sources 数组中使用的名称。可以通过传递模板字符串(template string)或者函数来完成
globalObject: "this",	这默认为 'window'，但是通过将其设置为 'this' 然后，构建的模块块也可以在 web worker 中工作。

optimization 配置代码

		optimization: {
			minimize: isEnvProduction,
			minimizer: [
				// This is only used in production mode
				new TerserPlugin({
					terserOptions: {
						parse: {
							// We want terser to parse ecma 8 code. However, we don't want it
							// to apply any minification steps that turns valid ecma 5 code
							// into invalid ecma 5 code. This is why the 'compress' and 'output'
							// sections only apply transformations that are ecma 5 safe
							// https://github.com/facebook/create-react-app/pull/4234
							ecma: 8,
						},
						compress: {
							ecma: 5,
							warnings: false,
							// Disabled because of an issue with Uglify breaking seemingly valid code:
							// https://github.com/facebook/create-react-app/issues/2376
							// Pending further investigation:
							// https://github.com/mishoo/UglifyJS2/issues/2011
							comparisons: false,
							// Disabled because of an issue with Terser breaking valid code:
							// https://github.com/facebook/create-react-app/issues/5250
							// Pending further investigation:
							// https://github.com/terser-js/terser/issues/120
							inline: 2,
						},
						mangle: {
							safari10: true,
						},
						// Added for profiling in devtools
						keep_classnames: isEnvProductionProfile,
						keep_fnames: isEnvProductionProfile,
						output: {
							ecma: 5,
							comments: false,
							// Turned on because emoji and regex is not minified properly using default
							// https://github.com/facebook/create-react-app/issues/2488
							ascii_only: true,
						},
					},
					sourceMap: shouldUseSourceMap,
				}),
				// This is only used in production mode
				new OptimizeCSSAssetsPlugin({
					cssProcessorOptions: {
						parser: safePostCssParser,
						map: shouldUseSourceMap
							? {
									// `inline: false` forces the sourcemap to be output into a
									// separate file
									inline: false,
									// `annotation: true` appends the sourceMappingURL to the end of
									// the css file, helping the browser find the sourcemap
									annotation: true,
							  }
							: false,
					},
					cssProcessorPluginOptions: {
						preset: [
							"default",
							{ minifyFontValues: { removeQuotes: false } },
						],
					},
				}),
			],
			// Automatically split vendor and commons
			// https://twitter.com/wSokra/status/969633336732905474
			// https://medium.com/webpack/webpack-4-code-splitting-chunk-graph-and-the-splitchunks-optimization-be739a861366
			splitChunks: {
				chunks: "all",
				name: isEnvDevelopment,
			},
			// Keep the runtime chunk separated to enable long term caching
			// https://twitter.com/wSokra/status/969679223278505985
			// https://github.com/facebook/create-react-app/issues/5358
			runtimeChunk: {
				name: (entrypoint) => `runtime-${entrypoint.name}`,
			},
		},

minimize: isEnvProduction,	告知 webpack 使用 TerserPlugin 或其它在 optimization.minimizer定义的插件压缩 bundle。
minimizer	仅用于生产模式。 TODO
resolve

module配置代码

module: {
			strictExportPresence: true,
			rules: [
				// Disable require.ensure as it's not a standard language feature.
				{ parser: { requireEnsure: false } },
				{
					// "oneOf" will traverse all following loaders until one will
					// match the requirements. When no loader matches it will fall
					// back to the "file" loader at the end of the loader list.
					oneOf: [
						// TODO: Merge this config once `image/avif` is in the mime-db
						// https://github.com/jshttp/mime-db
						{
							test: [/\.avif$/],
							loader: require.resolve("url-loader"),
							options: {
								limit: imageInlineSizeLimit,
								mimetype: "image/avif",
								name: "static/media/[name].[hash:8].[ext]",
							},
						},
						// "url" loader works like "file" loader except that it embeds assets
						// smaller than specified limit in bytes as data URLs to avoid requests.
						// A missing `test` is equivalent to a match.
						{
							test: [/\.bmp$/, /\.gif$/, /\.jpe?g$/, /\.png$/],
							loader: require.resolve("url-loader"),
							options: {
								limit: imageInlineSizeLimit,
								name: "static/media/[name].[hash:8].[ext]",
							},
						},
						// Process application JS with Babel.
						// The preset includes JSX, Flow, TypeScript, and some ESnext features.
						{
							test: /\.(js|mjs|jsx|ts|tsx)$/,
							include: paths.appSrc,
							loader: require.resolve("babel-loader"),
							options: {
								customize: require.resolve(
									"babel-preset-react-app/webpack-overrides"
								),
								presets: [
									[
										require.resolve(
											"babel-preset-react-app"
										),
										{
											runtime: hasJsxRuntime
												? "automatic"
												: "classic",
										},
									],
								],

								plugins: [
									[
										require.resolve(
											"babel-plugin-named-asset-import"
										),
										{
											loaderMap: {
												svg: {
													ReactComponent:
														"@svgr/webpack?-svgo,+titleProp,+ref![path]",
												},
											},
										},
									],
									isEnvDevelopment &&
										shouldUseReactRefresh &&
										require.resolve("react-refresh/babel"),
								].filter(Boolean),
								// This is a feature of `babel-loader` for webpack (not Babel itself).
								// It enables caching results in ./node_modules/.cache/babel-loader/
								// directory for faster rebuilds.
								cacheDirectory: true,
								// See #6846 for context on why cacheCompression is disabled
								cacheCompression: false,
								compact: isEnvProduction,
							},
						},
						// Process any JS outside of the app with Babel.
						// Unlike the application JS, we only compile the standard ES features.
						{
							test: /\.(js|mjs)$/,
							exclude: /@babel(?:\/|\\{1,2})runtime/,
							loader: require.resolve("babel-loader"),
							options: {
								babelrc: false,
								configFile: false,
								compact: false,
								presets: [
									[
										require.resolve(
											"babel-preset-react-app/dependencies"
										),
										{ helpers: true },
									],
								],
								cacheDirectory: true,
								// See #6846 for context on why cacheCompression is disabled
								cacheCompression: false,

								// Babel sourcemaps are needed for debugging into node_modules
								// code.  Without the options below, debuggers like VSCode
								// show incorrect code and set breakpoints on the wrong lines.
								sourceMaps: shouldUseSourceMap,
								inputSourceMap: shouldUseSourceMap,
							},
						},
						// "postcss" loader applies autoprefixer to our CSS.
						// "css" loader resolves paths in CSS and adds assets as dependencies.
						// "style" loader turns CSS into JS modules that inject <style> tags.
						// In production, we use MiniCSSExtractPlugin to extract that CSS
						// to a file, but in development "style" loader enables hot editing
						// of CSS.
						// By default we support CSS Modules with the extension .module.css
						{
							test: cssRegex,
							exclude: cssModuleRegex,
							use: getStyleLoaders({
								importLoaders: 1,
								sourceMap: isEnvProduction
									? shouldUseSourceMap
									: isEnvDevelopment,
							}),
							// Don't consider CSS imports dead code even if the
							// containing package claims to have no side effects.
							// Remove this when webpack adds a warning or an error for this.
							// See https://github.com/webpack/webpack/issues/6571
							sideEffects: true,
						},
						// Adds support for CSS Modules (https://github.com/css-modules/css-modules)
						// using the extension .module.css
						{
							test: cssModuleRegex,
							use: getStyleLoaders({
								importLoaders: 1,
								sourceMap: isEnvProduction
									? shouldUseSourceMap
									: isEnvDevelopment,
								modules: {
									getLocalIdent: getCSSModuleLocalIdent,
								},
							}),
						},
						// Opt-in support for SASS (using .scss or .sass extensions).
						// By default we support SASS Modules with the
						// extensions .module.scss or .module.sass
						{
							test: sassRegex,
							exclude: sassModuleRegex,
							use: getStyleLoaders(
								{
									importLoaders: 3,
									sourceMap: isEnvProduction
										? shouldUseSourceMap
										: isEnvDevelopment,
								},
								"sass-loader"
							),
							// Don't consider CSS imports dead code even if the
							// containing package claims to have no side effects.
							// Remove this when webpack adds a warning or an error for this.
							// See https://github.com/webpack/webpack/issues/6571
							sideEffects: true,
						},
						// Adds support for CSS Modules, but using SASS
						// using the extension .module.scss or .module.sass
						{
							test: sassModuleRegex,
							use: getStyleLoaders(
								{
									importLoaders: 3,
									sourceMap: isEnvProduction
										? shouldUseSourceMap
										: isEnvDevelopment,
									modules: {
										getLocalIdent: getCSSModuleLocalIdent,
									},
								},
								"sass-loader"
							),
						},
						// "file" loader makes sure those assets get served by WebpackDevServer.
						// When you `import` an asset, you get its (virtual) filename.
						// In production, they would get copied to the `build` folder.
						// This loader doesn't use a "test" so it will catch all modules
						// that fall through the other loaders.
						{
							loader: require.resolve("file-loader"),
							// Exclude `js` files to keep "css" loader working as it injects
							// its runtime that would otherwise be processed through "file" loader.
							// Also exclude `html` and `json` extensions so they get processed
							// by webpacks internal loaders.
							exclude: [
								/\.(js|mjs|jsx|ts|tsx)$/,
								/\.html$/,
								/\.json$/,
							],
							options: {
								name: "static/media/[name].[hash:8].[ext]",
							},
						},
						// ** STOP ** Are you adding a new loader?
						// Make sure to add the new loader(s) before the "file" loader.
					],
				},
			],
		},

这些选项决定了如何处理项目中的不同类型的模块。

devtool配置：

参考

值	含义
eval	每个模块被转化为字符串，在尾部添加//# souceURL（指明eval前文件）后，被eval包裹起来
source-map	最原始的source-map实现方式，打包代码的同时生成一个sourcemap文件，并在打包文件的末尾添加//# souceURL，注释会告诉JS引擎原始文件位置
hidden-source-map	打包结果与source-map一致，但是.map文件结尾不显示//# sourceMappingURL
inline-source-map	为打包前的每个文件添加sourcemap的dataUrl，追加到打包后文件内容的结尾；此处，dataUrl包含一个文件完整 souremap 信息的 Base64 格式化后的字符串
eval-source-map	将每个模块转化为字符串，使用eval包裹，并将打包前每个模块的sourcemap信息转换为Base64编码，拼接在每个打包后文件的结尾
cheap-source-map	同source-map,但不包含列信息，不包含 loader 的 sourcemap，（譬如 babel 的 sourcemap）
cheap-module-source-map	不包含列信息，同时 loader 的 sourcemap 也被简化为只包含对应行的。最终的 sourcemap 只有一份，它是 webpack 对 loader 生成的 sourcemap 进行简化，然后再次生成的

下面代码可以看到react-create-app，在生产环境 devtool为source-map或者为false，开发环境下为cheap-module-source-map。

总结

开发环境推荐使用：

1.eval ：每个模块使用eval()和//@ sourceURL执行。这是非常快。主要缺点是，它没有正确显示行号，因为它被映射到转换代码而不是原始代码(没有来自加载器的源映射)。

2.eval-source-map：每个模块使用eval()执行，而SourceMap作为DataUrl添加到eval()中。最初它是缓慢的，但是它提供快速的重建速度和产生真实的文件。行号被正确映射，因为它被映射到原始代码。它产生了最优质的开发资源。

3.cheap-eval-source-map：与eval-source-map类似，每个模块都使用eval()执行。它没有列映射，它只映射行号。它忽略了来自加载器的源代码，并且只显示与eval devtool相似的经过转换的代码。

4.cheap-module-eval-source-map：类似于cheap-eval-source-map，在本例中，来自加载器的源映射被处理以获得更好的结果。然而，加载器源映射被简化为每一行的单个映射。

生产环境推荐使用：

1.(none) ：(省略devtool选项)-不触发SourceMap。这是一个很好的选择。

2.source-map：一个完整的SourceMap是作为一个单独的文件。它为bundle 添加了引用注释，因此开发工具知道在哪里找到它。

3.hidden-source-map：与source-map相同，但不向bundle 添加引用注释。如果您只希望SourceMaps从错误报告中映射错误堆栈跟踪，但不想为浏览器开发工具暴露您的SourceMap，可以使用此选项。

4.nosources-source-map：一个SourceMap是在没有源代码的情况下创建的。它可以用于在客户机上映射堆栈跟踪，而不暴露所有源代码。您可以将源映射文件部署到webserver。

TODO。。。。。后续完善中

源代码

const fs = require("fs");
const path = require("path");
const webpack = require("webpack");
const resolve = require("resolve");
const PnpWebpackPlugin = require("pnp-webpack-plugin");
const HtmlWebpackPlugin = require("html-webpack-plugin");
const CaseSensitivePathsPlugin = require("case-sensitive-paths-webpack-plugin");
const InlineChunkHtmlPlugin = require("react-dev-utils/InlineChunkHtmlPlugin");
const TerserPlugin = require("terser-webpack-plugin");
const MiniCssExtractPlugin = require("mini-css-extract-plugin");
const OptimizeCSSAssetsPlugin = require("optimize-css-assets-webpack-plugin");
const safePostCssParser = require("postcss-safe-parser");
const ManifestPlugin = require("webpack-manifest-plugin");
const InterpolateHtmlPlugin = require("react-dev-utils/InterpolateHtmlPlugin");
const WorkboxWebpackPlugin = require("workbox-webpack-plugin");
const WatchMissingNodeModulesPlugin = require("react-dev-utils/WatchMissingNodeModulesPlugin");
const ModuleScopePlugin = require("react-dev-utils/ModuleScopePlugin");
const getCSSModuleLocalIdent = require("react-dev-utils/getCSSModuleLocalIdent");
const ESLintPlugin = require("eslint-webpack-plugin");
const paths = require("./paths");
const modules = require("./modules");
const getClientEnvironment = require("./env");
const ModuleNotFoundPlugin = require("react-dev-utils/ModuleNotFoundPlugin");
const ForkTsCheckerWebpackPlugin = require("react-dev-utils/ForkTsCheckerWebpackPlugin");
const typescriptFormatter = require("react-dev-utils/typescriptFormatter");
const ReactRefreshWebpackPlugin = require("@pmmmwh/react-refresh-webpack-plugin");

const postcssNormalize = require("postcss-normalize");

const appPackageJson = require(paths.appPackageJson);

// Source maps are resource heavy and can cause out of memory issue for large source files.
const shouldUseSourceMap = process.env.GENERATE_SOURCEMAP !== "false";

const webpackDevClientEntry = require.resolve(
	"react-dev-utils/webpackHotDevClient"
);
const reactRefreshOverlayEntry = require.resolve(
	"react-dev-utils/refreshOverlayInterop"
);

// Some apps do not need the benefits of saving a web request, so not inlining the chunk
// makes for a smoother build process.
const shouldInlineRuntimeChunk = process.env.INLINE_RUNTIME_CHUNK !== "false";

const emitErrorsAsWarnings = process.env.ESLINT_NO_DEV_ERRORS === "true";
const disableESLintPlugin = process.env.DISABLE_ESLINT_PLUGIN === "true";

const imageInlineSizeLimit = parseInt(
	process.env.IMAGE_INLINE_SIZE_LIMIT || "10000"
);

// Check if TypeScript is setup
const useTypeScript = fs.existsSync(paths.appTsConfig);

// Get the path to the uncompiled service worker (if it exists).
const swSrc = paths.swSrc;

// style files regexes
const cssRegex = /\.css$/;
const cssModuleRegex = /\.module\.css$/;
const sassRegex = /\.(scss|sass)$/;
const sassModuleRegex = /\.module\.(scss|sass)$/;

const hasJsxRuntime = (() => {
	if (process.env.DISABLE_NEW_JSX_TRANSFORM === "true") {
		return false;
	}

	try {
		require.resolve("react/jsx-runtime");
		return true;
	} catch (e) {
		return false;
	}
})();

// This is the production and development configuration.
// It is focused on developer experience, fast rebuilds, and a minimal bundle.
module.exports = function (webpackEnv) {
	const isEnvDevelopment = webpackEnv === "development";
	const isEnvProduction = webpackEnv === "production";

	// Variable used for enabling profiling in Production
	// passed into alias object. Uses a flag if passed into the build command
	const isEnvProductionProfile =
		isEnvProduction && process.argv.includes("--profile");

	// We will provide `paths.publicUrlOrPath` to our app
	// as %PUBLIC_URL% in `index.html` and `process.env.PUBLIC_URL` in JavaScript.
	// Omit trailing slash as %PUBLIC_URL%/xyz looks better than %PUBLIC_URL%xyz.
	// Get environment variables to inject into our app.
	const env = getClientEnvironment(paths.publicUrlOrPath.slice(0, -1));

	const shouldUseReactRefresh = env.raw.FAST_REFRESH;

	// common function to get style loaders
	const getStyleLoaders = (cssOptions, preProcessor) => {
		const loaders = [
			isEnvDevelopment && require.resolve("style-loader"),
			isEnvProduction && {
				loader: MiniCssExtractPlugin.loader,
				// css is located in `static/css`, use '../../' to locate index.html folder
				// in production `paths.publicUrlOrPath` can be a relative path
				options: paths.publicUrlOrPath.startsWith(".")
					? { publicPath: "../../" }
					: {},
			},
			{
				loader: require.resolve("css-loader"),
				options: cssOptions,
			},
			{
				// Options for PostCSS as we reference these options twice
				// Adds vendor prefixing based on your specified browser support in
				// package.json
				loader: require.resolve("postcss-loader"),
				options: {
					// Necessary for external CSS imports to work
					// https://github.com/facebook/create-react-app/issues/2677
					ident: "postcss",
					plugins: () => [
						require("postcss-flexbugs-fixes"),
						require("postcss-preset-env")({
							autoprefixer: {
								flexbox: "no-2009",
							},
							stage: 3,
						}),
						// Adds PostCSS Normalize as the reset css with default options,
						// so that it honors browserslist config in package.json
						// which in turn let's users customize the target behavior as per their needs.
						postcssNormalize(),
					],
					sourceMap: isEnvProduction
						? shouldUseSourceMap
						: isEnvDevelopment,
				},
			},
		].filter(Boolean);
		if (preProcessor) {
			loaders.push(
				{
					loader: require.resolve("resolve-url-loader"),
					options: {
						sourceMap: isEnvProduction
							? shouldUseSourceMap
							: isEnvDevelopment,
						root: paths.appSrc,
					},
				},
				{
					loader: require.resolve(preProcessor),
					options: {
						sourceMap: true,
					},
				}
			);
		}
		return loaders;
	};

	return {
		mode: isEnvProduction
			? "production"
			: isEnvDevelopment && "development",
		// Stop compilation early in production
		bail: isEnvProduction,
		devtool: isEnvProduction
			? shouldUseSourceMap
				? "source-map"
				: false
			: isEnvDevelopment && "cheap-module-source-map",
		// These are the "entry points" to our application.
		// This means they will be the "root" imports that are included in JS bundle.
		entry:
			isEnvDevelopment && !shouldUseReactRefresh
				? [
						// Include an alternative client for WebpackDevServer. A client's job is to
						// connect to WebpackDevServer by a socket and get notified about changes.
						// When you save a file, the client will either apply hot updates (in case
						// of CSS changes), or refresh the page (in case of JS changes). When you
						// make a syntax error, this client will display a syntax error overlay.
						// Note: instead of the default WebpackDevServer client, we use a custom one
						// to bring better experience for Create React App users. You can replace
						// the line below with these two lines if you prefer the stock client:
						//
						// require.resolve('webpack-dev-server/client') + '?/',
						// require.resolve('webpack/hot/dev-server'),
						//
						// When using the experimental react-refresh integration,
						// the webpack plugin takes care of injecting the dev client for us.
						webpackDevClientEntry,
						// Finally, this is your app's code:
						paths.appIndexJs,
						// We include the app code last so that if there is a runtime error during
						// initialization, it doesn't blow up the WebpackDevServer client, and
						// changing JS code would still trigger a refresh.
				  ]
				: paths.appIndexJs,
		output: {
			// The build folder.
			path: isEnvProduction ? paths.appBuild : undefined,
			// Add /* filename */ comments to generated require()s in the output.
			pathinfo: isEnvDevelopment,
			// There will be one main bundle, and one file per asynchronous chunk.
			// In development, it does not produce real files.
			filename: isEnvProduction
				? "static/js/[name].[contenthash:8].js"
				: isEnvDevelopment && "static/js/bundle.js",
			// TODO: remove this when upgrading to webpack 5
			futureEmitAssets: true,
			// There are also additional JS chunk files if you use code splitting.
			chunkFilename: isEnvProduction
				? "static/js/[name].[contenthash:8].chunk.js"
				: isEnvDevelopment && "static/js/[name].chunk.js",
			// webpack uses `publicPath` to determine where the app is being served from.
			// It requires a trailing slash, or the file assets will get an incorrect path.
			// We inferred the "public path" (such as / or /my-project) from homepage.
			publicPath: paths.publicUrlOrPath,
			// Point sourcemap entries to original disk location (format as URL on Windows)
			devtoolModuleFilenameTemplate: isEnvProduction
				? (info) =>
						path
							.relative(paths.appSrc, info.absoluteResourcePath)
							.replace(/\\/g, "/")
				: isEnvDevelopment &&
				  ((info) =>
						path
							.resolve(info.absoluteResourcePath)
							.replace(/\\/g, "/")),
			// Prevents conflicts when multiple webpack runtimes (from different apps)
			// are used on the same page.
			jsonpFunction: `webpackJsonp${appPackageJson.name}`,
			// this defaults to 'window', but by setting it to 'this' then
			// module chunks which are built will work in web workers as well.
			globalObject: "this",
		},
		optimization: {
			minimize: isEnvProduction,
			minimizer: [
				// This is only used in production mode
				new TerserPlugin({
					terserOptions: {
						parse: {
							// We want terser to parse ecma 8 code. However, we don't want it
							// to apply any minification steps that turns valid ecma 5 code
							// into invalid ecma 5 code. This is why the 'compress' and 'output'
							// sections only apply transformations that are ecma 5 safe
							// https://github.com/facebook/create-react-app/pull/4234
							ecma: 8,
						},
						compress: {
							ecma: 5,
							warnings: false,
							// Disabled because of an issue with Uglify breaking seemingly valid code:
							// https://github.com/facebook/create-react-app/issues/2376
							// Pending further investigation:
							// https://github.com/mishoo/UglifyJS2/issues/2011
							comparisons: false,
							// Disabled because of an issue with Terser breaking valid code:
							// https://github.com/facebook/create-react-app/issues/5250
							// Pending further investigation:
							// https://github.com/terser-js/terser/issues/120
							inline: 2,
						},
						mangle: {
							safari10: true,
						},
						// Added for profiling in devtools
						keep_classnames: isEnvProductionProfile,
						keep_fnames: isEnvProductionProfile,
						output: {
							ecma: 5,
							comments: false,
							// Turned on because emoji and regex is not minified properly using default
							// https://github.com/facebook/create-react-app/issues/2488
							ascii_only: true,
						},
					},
					sourceMap: shouldUseSourceMap,
				}),
				// This is only used in production mode
				new OptimizeCSSAssetsPlugin({
					cssProcessorOptions: {
						parser: safePostCssParser,
						map: shouldUseSourceMap
							? {
									// `inline: false` forces the sourcemap to be output into a
									// separate file
									inline: false,
									// `annotation: true` appends the sourceMappingURL to the end of
									// the css file, helping the browser find the sourcemap
									annotation: true,
							  }
							: false,
					},
					cssProcessorPluginOptions: {
						preset: [
							"default",
							{ minifyFontValues: { removeQuotes: false } },
						],
					},
				}),
			],
			// Automatically split vendor and commons
			// https://twitter.com/wSokra/status/969633336732905474
			// https://medium.com/webpack/webpack-4-code-splitting-chunk-graph-and-the-splitchunks-optimization-be739a861366
			splitChunks: {
				chunks: "all",
				name: isEnvDevelopment,
			},
			// Keep the runtime chunk separated to enable long term caching
			// https://twitter.com/wSokra/status/969679223278505985
			// https://github.com/facebook/create-react-app/issues/5358
			runtimeChunk: {
				name: (entrypoint) => `runtime-${entrypoint.name}`,
			},
		},
		resolve: {
			// This allows you to set a fallback for where webpack should look for modules.
			// We placed these paths second because we want `node_modules` to "win"
			// if there are any conflicts. This matches Node resolution mechanism.
			// https://github.com/facebook/create-react-app/issues/253
			modules: ["node_modules", paths.appNodeModules].concat(
				modules.additionalModulePaths || []
			),
			// These are the reasonable defaults supported by the Node ecosystem.
			// We also include JSX as a common component filename extension to support
			// some tools, although we do not recommend using it, see:
			// https://github.com/facebook/create-react-app/issues/290
			// `web` extension prefixes have been added for better support
			// for React Native Web.
			extensions: paths.moduleFileExtensions
				.map((ext) => `.${ext}`)
				.filter((ext) => useTypeScript || !ext.includes("ts")),
			alias: {
				// Support React Native Web
				// https://www.smashingmagazine.com/2016/08/a-glimpse-into-the-future-with-react-native-for-web/
				"react-native": "react-native-web",
				// Allows for better profiling with ReactDevTools
				...(isEnvProductionProfile && {
					"react-dom$": "react-dom/profiling",
					"scheduler/tracing": "scheduler/tracing-profiling",
				}),
				...(modules.webpackAliases || {}),
			},
			plugins: [
				// Adds support for installing with Plug'n'Play, leading to faster installs and adding
				// guards against forgotten dependencies and such.
				PnpWebpackPlugin,
				// Prevents users from importing files from outside of src/ (or node_modules/).
				// This often causes confusion because we only process files within src/ with babel.
				// To fix this, we prevent you from importing files out of src/ -- if you'd like to,
				// please link the files into your node_modules/ and let module-resolution kick in.
				// Make sure your source files are compiled, as they will not be processed in any way.
				new ModuleScopePlugin(paths.appSrc, [
					paths.appPackageJson,
					reactRefreshOverlayEntry,
				]),
			],
		},
		resolveLoader: {
			plugins: [
				// Also related to Plug'n'Play, but this time it tells webpack to load its loaders
				// from the current package.
				PnpWebpackPlugin.moduleLoader(module),
			],
		},
		module: {
			strictExportPresence: true,
			rules: [
				// Disable require.ensure as it's not a standard language feature.
				{ parser: { requireEnsure: false } },
				{
					// "oneOf" will traverse all following loaders until one will
					// match the requirements. When no loader matches it will fall
					// back to the "file" loader at the end of the loader list.
					oneOf: [
						// TODO: Merge this config once `image/avif` is in the mime-db
						// https://github.com/jshttp/mime-db
						{
							test: [/\.avif$/],
							loader: require.resolve("url-loader"),
							options: {
								limit: imageInlineSizeLimit,
								mimetype: "image/avif",
								name: "static/media/[name].[hash:8].[ext]",
							},
						},
						// "url" loader works like "file" loader except that it embeds assets
						// smaller than specified limit in bytes as data URLs to avoid requests.
						// A missing `test` is equivalent to a match.
						{
							test: [/\.bmp$/, /\.gif$/, /\.jpe?g$/, /\.png$/],
							loader: require.resolve("url-loader"),
							options: {
								limit: imageInlineSizeLimit,
								name: "static/media/[name].[hash:8].[ext]",
							},
						},
						// Process application JS with Babel.
						// The preset includes JSX, Flow, TypeScript, and some ESnext features.
						{
							test: /\.(js|mjs|jsx|ts|tsx)$/,
							include: paths.appSrc,
							loader: require.resolve("babel-loader"),
							options: {
								customize: require.resolve(
									"babel-preset-react-app/webpack-overrides"
								),
								presets: [
									[
										require.resolve(
											"babel-preset-react-app"
										),
										{
											runtime: hasJsxRuntime
												? "automatic"
												: "classic",
										},
									],
								],

								plugins: [
									[
										require.resolve(
											"babel-plugin-named-asset-import"
										),
										{
											loaderMap: {
												svg: {
													ReactComponent:
														"@svgr/webpack?-svgo,+titleProp,+ref![path]",
												},
											},
										},
									],
									isEnvDevelopment &&
										shouldUseReactRefresh &&
										require.resolve("react-refresh/babel"),
								].filter(Boolean),
								// This is a feature of `babel-loader` for webpack (not Babel itself).
								// It enables caching results in ./node_modules/.cache/babel-loader/
								// directory for faster rebuilds.
								cacheDirectory: true,
								// See #6846 for context on why cacheCompression is disabled
								cacheCompression: false,
								compact: isEnvProduction,
							},
						},
						// Process any JS outside of the app with Babel.
						// Unlike the application JS, we only compile the standard ES features.
						{
							test: /\.(js|mjs)$/,
							exclude: /@babel(?:\/|\\{1,2})runtime/,
							loader: require.resolve("babel-loader"),
							options: {
								babelrc: false,
								configFile: false,
								compact: false,
								presets: [
									[
										require.resolve(
											"babel-preset-react-app/dependencies"
										),
										{ helpers: true },
									],
								],
								cacheDirectory: true,
								// See #6846 for context on why cacheCompression is disabled
								cacheCompression: false,

								// Babel sourcemaps are needed for debugging into node_modules
								// code.  Without the options below, debuggers like VSCode
								// show incorrect code and set breakpoints on the wrong lines.
								sourceMaps: shouldUseSourceMap,
								inputSourceMap: shouldUseSourceMap,
							},
						},
						// "postcss" loader applies autoprefixer to our CSS.
						// "css" loader resolves paths in CSS and adds assets as dependencies.
						// "style" loader turns CSS into JS modules that inject <style> tags.
						// In production, we use MiniCSSExtractPlugin to extract that CSS
						// to a file, but in development "style" loader enables hot editing
						// of CSS.
						// By default we support CSS Modules with the extension .module.css
						{
							test: cssRegex,
							exclude: cssModuleRegex,
							use: getStyleLoaders({
								importLoaders: 1,
								sourceMap: isEnvProduction
									? shouldUseSourceMap
									: isEnvDevelopment,
							}),
							// Don't consider CSS imports dead code even if the
							// containing package claims to have no side effects.
							// Remove this when webpack adds a warning or an error for this.
							// See https://github.com/webpack/webpack/issues/6571
							sideEffects: true,
						},
						// Adds support for CSS Modules (https://github.com/css-modules/css-modules)
						// using the extension .module.css
						{
							test: cssModuleRegex,
							use: getStyleLoaders({
								importLoaders: 1,
								sourceMap: isEnvProduction
									? shouldUseSourceMap
									: isEnvDevelopment,
								modules: {
									getLocalIdent: getCSSModuleLocalIdent,
								},
							}),
						},
						// Opt-in support for SASS (using .scss or .sass extensions).
						// By default we support SASS Modules with the
						// extensions .module.scss or .module.sass
						{
							test: sassRegex,
							exclude: sassModuleRegex,
							use: getStyleLoaders(
								{
									importLoaders: 3,
									sourceMap: isEnvProduction
										? shouldUseSourceMap
										: isEnvDevelopment,
								},
								"sass-loader"
							),
							// Don't consider CSS imports dead code even if the
							// containing package claims to have no side effects.
							// Remove this when webpack adds a warning or an error for this.
							// See https://github.com/webpack/webpack/issues/6571
							sideEffects: true,
						},
						// Adds support for CSS Modules, but using SASS
						// using the extension .module.scss or .module.sass
						{
							test: sassModuleRegex,
							use: getStyleLoaders(
								{
									importLoaders: 3,
									sourceMap: isEnvProduction
										? shouldUseSourceMap
										: isEnvDevelopment,
									modules: {
										getLocalIdent: getCSSModuleLocalIdent,
									},
								},
								"sass-loader"
							),
						},
						// "file" loader makes sure those assets get served by WebpackDevServer.
						// When you `import` an asset, you get its (virtual) filename.
						// In production, they would get copied to the `build` folder.
						// This loader doesn't use a "test" so it will catch all modules
						// that fall through the other loaders.
						{
							loader: require.resolve("file-loader"),
							// Exclude `js` files to keep "css" loader working as it injects
							// its runtime that would otherwise be processed through "file" loader.
							// Also exclude `html` and `json` extensions so they get processed
							// by webpacks internal loaders.
							exclude: [
								/\.(js|mjs|jsx|ts|tsx)$/,
								/\.html$/,
								/\.json$/,
							],
							options: {
								name: "static/media/[name].[hash:8].[ext]",
							},
						},
						// ** STOP ** Are you adding a new loader?
						// Make sure to add the new loader(s) before the "file" loader.
					],
				},
			],
		},
		plugins: [
			// Generates an `index.html` file with the <script> injected.
			new HtmlWebpackPlugin(
				Object.assign(
					{},
					{
						inject: true,
						template: paths.appHtml,
					},
					isEnvProduction
						? {
								minify: {
									removeComments: true,
									collapseWhitespace: true,
									removeRedundantAttributes: true,
									useShortDoctype: true,
									removeEmptyAttributes: true,
									removeStyleLinkTypeAttributes: true,
									keepClosingSlash: true,
									minifyJS: true,
									minifyCSS: true,
									minifyURLs: true,
								},
						  }
						: undefined
				)
			),
			// Inlines the webpack runtime script. This script is too small to warrant
			// a network request.
			// https://github.com/facebook/create-react-app/issues/5358
			isEnvProduction &&
				shouldInlineRuntimeChunk &&
				new InlineChunkHtmlPlugin(HtmlWebpackPlugin, [
					/runtime-.+[.]js/,
				]),
			// Makes some environment variables available in index.html.
			// The public URL is available as %PUBLIC_URL% in index.html, e.g.:
			// <link rel="icon" href="%PUBLIC_URL%/favicon.ico">
			// It will be an empty string unless you specify "homepage"
			// in `package.json`, in which case it will be the pathname of that URL.
			new InterpolateHtmlPlugin(HtmlWebpackPlugin, env.raw),
			// This gives some necessary context to module not found errors, such as
			// the requesting resource.
			new ModuleNotFoundPlugin(paths.appPath),
			// Makes some environment variables available to the JS code, for example:
			// if (process.env.NODE_ENV === 'production') { ... }. See `./env.js`.
			// It is absolutely essential that NODE_ENV is set to production
			// during a production build.
			// Otherwise React will be compiled in the very slow development mode.
			new webpack.DefinePlugin(env.stringified),
			// This is necessary to emit hot updates (CSS and Fast Refresh):
			isEnvDevelopment && new webpack.HotModuleReplacementPlugin(),
			// Experimental hot reloading for React .
			// https://github.com/facebook/react/tree/master/packages/react-refresh
			isEnvDevelopment &&
				shouldUseReactRefresh &&
				new ReactRefreshWebpackPlugin({
					overlay: {
						entry: webpackDevClientEntry,
						// The expected exports are slightly different from what the overlay exports,
						// so an interop is included here to enable feedback on module-level errors.
						module: reactRefreshOverlayEntry,
						// Since we ship a custom dev client and overlay integration,
						// the bundled socket handling logic can be eliminated.
						sockIntegration: false,
					},
				}),
			// Watcher doesn't work well if you mistype casing in a path so we use
			// a plugin that prints an error when you attempt to do this.
			// See https://github.com/facebook/create-react-app/issues/240
			isEnvDevelopment && new CaseSensitivePathsPlugin(),
			// If you require a missing module and then `npm install` it, you still have
			// to restart the development server for webpack to discover it. This plugin
			// makes the discovery automatic so you don't have to restart.
			// See https://github.com/facebook/create-react-app/issues/186
			isEnvDevelopment &&
				new WatchMissingNodeModulesPlugin(paths.appNodeModules),
			isEnvProduction &&
				new MiniCssExtractPlugin({
					// Options similar to the same options in webpackOptions.output
					// both options are optional
					filename: "static/css/[name].[contenthash:8].css",
					chunkFilename:
						"static/css/[name].[contenthash:8].chunk.css",
				}),
			// Generate an asset manifest file with the following content:
			// - "files" key: Mapping of all asset filenames to their corresponding
			//   output file so that tools can pick it up without having to parse
			//   `index.html`
			// - "entrypoints" key: Array of files which are included in `index.html`,
			//   can be used to reconstruct the HTML if necessary
			new ManifestPlugin({
				fileName: "asset-manifest.json",
				publicPath: paths.publicUrlOrPath,
				generate: (seed, files, entrypoints) => {
					const manifestFiles = files.reduce((manifest, file) => {
						manifest[file.name] = file.path;
						return manifest;
					}, seed);
					const entrypointFiles = entrypoints.main.filter(
						(fileName) => !fileName.endsWith(".map")
					);

					return {
						files: manifestFiles,
						entrypoints: entrypointFiles,
					};
				},
			}),
			// Moment.js is an extremely popular library that bundles large locale files
			// by default due to how webpack interprets its code. This is a practical
			// solution that requires the user to opt into importing specific locales.
			// https://github.com/jmblog/how-to-optimize-momentjs-with-webpack
			// You can remove this if you don't use Moment.js:
			new webpack.IgnorePlugin(/^\.\/locale$/, /moment$/),
			// Generate a service worker script that will precache, and keep up to date,
			// the HTML & assets that are part of the webpack build.
			isEnvProduction &&
				fs.existsSync(swSrc) &&
				new WorkboxWebpackPlugin.InjectManifest({
					swSrc,
					dontCacheBustURLsMatching: /\.[0-9a-f]{8}\./,
					exclude: [/\.map$/, /asset-manifest\.json$/, /LICENSE/],
					// Bump up the default maximum size (2mb) that's precached,
					// to make lazy-loading failure scenarios less likely.
					// See https://github.com/cra-template/pwa/issues/13#issuecomment-722667270
					maximumFileSizeToCacheInBytes: 5 * 1024 * 1024,
				}),
			// TypeScript type checking
			useTypeScript &&
				new ForkTsCheckerWebpackPlugin({
					typescript: resolve.sync("typescript", {
						basedir: paths.appNodeModules,
					}),
					async: isEnvDevelopment,
					checkSyntacticErrors: true,
					resolveModuleNameModule: process.versions.pnp
						? `${__dirname}/pnpTs.js`
						: undefined,
					resolveTypeReferenceDirectiveModule: process.versions.pnp
						? `${__dirname}/pnpTs.js`
						: undefined,
					tsconfig: paths.appTsConfig,
					reportFiles: [
						// This one is specifically to match during CI tests,
						// as micromatch doesn't match
						// '../cra-template-typescript/template/src/App.tsx'
						// otherwise.
						"../**/src/**/*.{ts,tsx}",
						"**/src/**/*.{ts,tsx}",
						"!**/src/**/__tests__/**",
						"!**/src/**/?(*.)(spec|test).*",
						"!**/src/setupProxy.*",
						"!**/src/setupTests.*",
					],
					silent: true,
					// The formatter is invoked directly in WebpackDevServerUtils during development
					formatter: isEnvProduction
						? typescriptFormatter
						: undefined,
				}),
			!disableESLintPlugin &&
				new ESLintPlugin({
					// Plugin options
					extensions: ["js", "mjs", "jsx", "ts", "tsx"],
					formatter: require.resolve(
						"react-dev-utils/eslintFormatter"
					),
					eslintPath: require.resolve("eslint"),
					failOnError: !(isEnvDevelopment && emitErrorsAsWarnings),
					context: paths.appSrc,
					cache: true,
					cacheLocation: path.resolve(
						paths.appNodeModules,
						".cache/.eslintcache"
					),
					// ESLint class options
					cwd: paths.appPath,
					resolvePluginsRelativeTo: __dirname,
					baseConfig: {
						extends: [
							require.resolve("eslint-config-react-app/base"),
						],
						rules: {
							...(!hasJsxRuntime && {
								"react/react-in-jsx-scope": "error",
							}),
						},
					},
				}),
		].filter(Boolean),
		// Some libraries import Node modules but don't use them in the browser.
		// Tell webpack to provide empty mocks for them so importing them works.
		node: {
			module: "empty",
			dgram: "empty",
			dns: "mock",
			fs: "empty",
			http2: "empty",
			net: "empty",
			tls: "empty",
			child_process: "empty",
		},
		// Turn off performance processing because we utilize
		// our own hints via the FileSizeReporter
		performance: false,
	};
};