暴露配置

config/env.js

+'use strict';
+
+const fs = require('fs');
+const path = require('path');
+const paths = require('./paths');
+
+// Make sure that including paths.js after env.js will read .env variables.
+delete require.cache[require.resolve('./paths')];
+
+const NODE_ENV = process.env.NODE_ENV;
+if (!NODE_ENV) {
+  throw new Error(
+    'The NODE_ENV environment variable is required but was not specified.'
+  );
+}
+
+// https://github.com/bkeepers/dotenv#what-other-env-files-can-i-use
+const dotenvFiles = [
+  `${paths.dotenv}.${NODE_ENV}.local`,
+  // Don't include `.env.local` for `test` environment
+  // since normally you expect tests to produce the same
+  // results for everyone
+  NODE_ENV !== 'test' && `${paths.dotenv}.local`,
+  `${paths.dotenv}.${NODE_ENV}`,
+  paths.dotenv,
+].filter(Boolean);
+
+// Load environment variables from .env* files. Suppress warnings using silent
+// if this file is missing. dotenv will never modify any environment variables
+// that have already been set.  Variable expansion is supported in .env files.
+// https://github.com/motdotla/dotenv
+// https://github.com/motdotla/dotenv-expand
+dotenvFiles.forEach(dotenvFile => {
+  if (fs.existsSync(dotenvFile)) {
+    require('dotenv-expand')(
+      require('dotenv').config({
+        path: dotenvFile,
+      })
+    );
+  }
+});
+
+// We support resolving modules according to `NODE_PATH`.
+// This lets you use absolute paths in imports inside large monorepos:
+// https://github.com/facebook/create-react-app/issues/253.
+// It works similar to `NODE_PATH` in Node itself:
+// https://nodejs.org/api/modules.html#modules_loading_from_the_global_folders
+// Note that unlike in Node, only *relative* paths from `NODE_PATH` are honored.
+// Otherwise, we risk importing Node.js core modules into an app instead of webpack shims.
+// https://github.com/facebook/create-react-app/issues/1023#issuecomment-265344421
+// We also resolve them to make sure all tools using them work consistently.
+const appDirectory = fs.realpathSync(process.cwd());
+process.env.NODE_PATH = (process.env.NODE_PATH || '')
+  .split(path.delimiter)
+  .filter(folder => folder && !path.isAbsolute(folder))
+  .map(folder => path.resolve(appDirectory, folder))
+  .join(path.delimiter);
+
+// Grab NODE_ENV and REACT_APP_* environment variables and prepare them to be
+// injected into the application via DefinePlugin in webpack configuration.
+const REACT_APP = /^REACT_APP_/i;
+
+function getClientEnvironment(publicUrl) {
+  const raw = Object.keys(process.env)
+    .filter(key => REACT_APP.test(key))
+    .reduce(
+      (env, key) => {
+        env[key] = process.env[key];
+        return env;
+      },
+      {
+        // Useful for determining whether we’re running in production mode.
+        // Most importantly, it switches React into the correct mode.
+        NODE_ENV: process.env.NODE_ENV || 'development',
+        // Useful for resolving the correct path to static assets in `public`.
+        // For example, <img src={process.env.PUBLIC_URL + '/img/logo.png'} />.
+        // This should only be used as an escape hatch. Normally you would put
+        // images into the `src` and `import` them in code to get their paths.
+        PUBLIC_URL: publicUrl,
+        // We support configuring the sockjs pathname during development.
+        // These settings let a developer run multiple simultaneous projects.
+        // They are used as the connection `hostname`, `pathname` and `port`
+        // in webpackHotDevClient. They are used as the `sockHost`, `sockPath`
+        // and `sockPort` options in webpack-dev-server.
+        WDS_SOCKET_HOST: process.env.WDS_SOCKET_HOST,
+        WDS_SOCKET_PATH: process.env.WDS_SOCKET_PATH,
+        WDS_SOCKET_PORT: process.env.WDS_SOCKET_PORT,
+        // Whether or not react-refresh is enabled.
+        // react-refresh is not 100% stable at this time,
+        // which is why it's disabled by default.
+        // It is defined here so it is available in the webpackHotDevClient.
+        FAST_REFRESH: process.env.FAST_REFRESH !== 'false',
+      }
+    );
+  // Stringify all values so we can feed into webpack DefinePlugin
+  const stringified = {
+    'process.env': Object.keys(raw).reduce((env, key) => {
+      env[key] = JSON.stringify(raw[key]);
+      return env;
+    }, {}),
+  };
+
+  return { raw, stringified };
+}
+
+module.exports = getClientEnvironment;

config/getHttpsConfig.js

+'use strict';
+
+const fs = require('fs');
+const path = require('path');
+const crypto = require('crypto');
+const chalk = require('react-dev-utils/chalk');
+const paths = require('./paths');
+
+// Ensure the certificate and key provided are valid and if not
+// throw an easy to debug error
+function validateKeyAndCerts({ cert, key, keyFile, crtFile }) {
+  let encrypted;
+  try {
+    // publicEncrypt will throw an error with an invalid cert
+    encrypted = crypto.publicEncrypt(cert, Buffer.from('test'));
+  } catch (err) {
+    throw new Error(
+      `The certificate "${chalk.yellow(crtFile)}" is invalid.\n${err.message}`
+    );
+  }
+
+  try {
+    // privateDecrypt will throw an error with an invalid key
+    crypto.privateDecrypt(key, encrypted);
+  } catch (err) {
+    throw new Error(
+      `The certificate key "${chalk.yellow(keyFile)}" is invalid.\n${
+        err.message
+      }`
+    );
+  }
+}
+
+// Read file and throw an error if it doesn't exist
+function readEnvFile(file, type) {
+  if (!fs.existsSync(file)) {
+    throw new Error(
+      `You specified ${chalk.cyan(
+        type
+      )} in your env, but the file "${chalk.yellow(file)}" can't be found.`
+    );
+  }
+  return fs.readFileSync(file);
+}
+
+// Get the https config
+// Return cert files if provided in env, otherwise just true or false
+function getHttpsConfig() {
+  const { SSL_CRT_FILE, SSL_KEY_FILE, HTTPS } = process.env;
+  const isHttps = HTTPS === 'true';
+
+  if (isHttps && SSL_CRT_FILE && SSL_KEY_FILE) {
+    const crtFile = path.resolve(paths.appPath, SSL_CRT_FILE);
+    const keyFile = path.resolve(paths.appPath, SSL_KEY_FILE);
+    const config = {
+      cert: readEnvFile(crtFile, 'SSL_CRT_FILE'),
+      key: readEnvFile(keyFile, 'SSL_KEY_FILE'),
+    };
+
+    validateKeyAndCerts({ ...config, keyFile, crtFile });
+    return config;
+  }
+  return isHttps;
+}
+
+module.exports = getHttpsConfig;

config/jest/cssTransform.js

+'use strict';
+
+// This is a custom Jest transformer turning style imports into empty objects.
+// http://facebook.github.io/jest/docs/en/webpack.html
+
+module.exports = {
+  process() {
+    return 'module.exports = {};';
+  },
+  getCacheKey() {
+    // The output is always the same.
+    return 'cssTransform';
+  },
+};

config/jest/fileTransform.js

+'use strict';
+
+const path = require('path');
+const camelcase = require('camelcase');
+
+// This is a custom Jest transformer turning file imports into filenames.
+// http://facebook.github.io/jest/docs/en/webpack.html
+
+module.exports = {
+  process(src, filename) {
+    const assetFilename = JSON.stringify(path.basename(filename));
+
+    if (filename.match(/\.svg$/)) {
+      // Based on how SVGR generates a component name:
+      // https://github.com/smooth-code/svgr/blob/01b194cf967347d43d4cbe6b434404731b87cf27/packages/core/src/state.js#L6
+      const pascalCaseFilename = camelcase(path.parse(filename).name, {
+        pascalCase: true,
+      });
+      const componentName = `Svg${pascalCaseFilename}`;
+      return `const React = require('react');
+      module.exports = {
+        __esModule: true,
+        default: ${assetFilename},
+        ReactComponent: React.forwardRef(function ${componentName}(props, ref) {
+          return {
+            $$typeof: Symbol.for('react.element'),
+            type: 'svg',
+            ref: ref,
+            key: null,
+            props: Object.assign({}, props, {
+              children: ${assetFilename}
+            })
+          };
+        }),
+      };`;
+    }
+
+    return `module.exports = ${assetFilename};`;
+  },
+};

config/modules.js

+'use strict';
+
+const fs = require('fs');
+const path = require('path');
+const paths = require('./paths');
+const chalk = require('react-dev-utils/chalk');
+const resolve = require('resolve');
+
+/**
+ * Get additional module paths based on the baseUrl of a compilerOptions object.
+ *
+ * @param {Object} options
+ */
+function getAdditionalModulePaths(options = {}) {
+  const baseUrl = options.baseUrl;
+
+  if (!baseUrl) {
+    return '';
+  }
+
+  const baseUrlResolved = path.resolve(paths.appPath, baseUrl);
+
+  // We don't need to do anything if `baseUrl` is set to `node_modules`. This is
+  // the default behavior.
+  if (path.relative(paths.appNodeModules, baseUrlResolved) === '') {
+    return null;
+  }
+
+  // Allow the user set the `baseUrl` to `appSrc`.
+  if (path.relative(paths.appSrc, baseUrlResolved) === '') {
+    return [paths.appSrc];
+  }
+
+  // If the path is equal to the root directory we ignore it here.
+  // We don't want to allow importing from the root directly as source files are
+  // not transpiled outside of `src`. We do allow importing them with the
+  // absolute path (e.g. `src/Components/Button.js`) but we set that up with
+  // an alias.
+  if (path.relative(paths.appPath, baseUrlResolved) === '') {
+    return null;
+  }
+
+  // Otherwise, throw an error.
+  throw new Error(
+    chalk.red.bold(
+      "Your project's `baseUrl` can only be set to `src` or `node_modules`." +
+        ' Create React App does not support other values at this time.'
+    )
+  );
+}
+
+/**
+ * Get webpack aliases based on the baseUrl of a compilerOptions object.
+ *
+ * @param {*} options
+ */
+function getWebpackAliases(options = {}) {
+  const baseUrl = options.baseUrl;
+
+  if (!baseUrl) {
+    return {};
+  }
+
+  const baseUrlResolved = path.resolve(paths.appPath, baseUrl);
+
+  if (path.relative(paths.appPath, baseUrlResolved) === '') {
+    return {
+      src: paths.appSrc,
+    };
+  }
+}
+
+/**
+ * Get jest aliases based on the baseUrl of a compilerOptions object.
+ *
+ * @param {*} options
+ */
+function getJestAliases(options = {}) {
+  const baseUrl = options.baseUrl;
+
+  if (!baseUrl) {
+    return {};
+  }
+
+  const baseUrlResolved = path.resolve(paths.appPath, baseUrl);
+
+  if (path.relative(paths.appPath, baseUrlResolved) === '') {
+    return {
+      '^src/(.*)$': '<rootDir>/src/$1',
+    };
+  }
+}
+
+function getModules() {
+  // Check if TypeScript is setup
+  const hasTsConfig = fs.existsSync(paths.appTsConfig);
+  const hasJsConfig = fs.existsSync(paths.appJsConfig);
+
+  if (hasTsConfig && hasJsConfig) {
+    throw new Error(
+      'You have both a tsconfig.json and a jsconfig.json. If you are using TypeScript please remove your jsconfig.json file.'
+    );
+  }
+
+  let config;
+
+  // If there's a tsconfig.json we assume it's a
+  // TypeScript project and set up the config
+  // based on tsconfig.json
+  if (hasTsConfig) {
+    const ts = require(resolve.sync('typescript', {
+      basedir: paths.appNodeModules,
+    }));
+    config = ts.readConfigFile(paths.appTsConfig, ts.sys.readFile).config;
+    // Otherwise we'll check if there is jsconfig.json
+    // for non TS projects.
+  } else if (hasJsConfig) {
+    config = require(paths.appJsConfig);
+  }
+
+  config = config || {};
+  const options = config.compilerOptions || {};
+
+  const additionalModulePaths = getAdditionalModulePaths(options);
+
+  return {
+    additionalModulePaths: additionalModulePaths,
+    webpackAliases: getWebpackAliases(options),
+    jestAliases: getJestAliases(options),
+    hasTsConfig,
+  };
+}
+
+module.exports = getModules();

config/paths.js

+'use strict';
+
+const path = require('path');
+const fs = require('fs');
+const getPublicUrlOrPath = require('react-dev-utils/getPublicUrlOrPath');
+
+// Make sure any symlinks in the project folder are resolved:
+// https://github.com/facebook/create-react-app/issues/637
+const appDirectory = fs.realpathSync(process.cwd());
+const resolveApp = relativePath => path.resolve(appDirectory, relativePath);
+
+// We use `PUBLIC_URL` environment variable or "homepage" field to infer
+// "public path" at which the app is served.
+// webpack needs to know it to put the right <script> hrefs into HTML even in
+// single-page apps that may serve index.html for nested URLs like /todos/42.
+// We can't use a relative path in HTML because we don't want to load something
+// like /todos/42/static/js/bundle.7289d.js. We have to know the root.
+const publicUrlOrPath = getPublicUrlOrPath(
+  process.env.NODE_ENV === 'development',
+  require(resolveApp('package.json')).homepage,
+  process.env.PUBLIC_URL
+);
+
+const moduleFileExtensions = [
+  'web.mjs',
+  'mjs',
+  'web.js',
+  'js',
+  'web.ts',
+  'ts',
+  'web.tsx',
+  'tsx',
+  'json',
+  'web.jsx',
+  'jsx',
+];
+
+// Resolve file paths in the same order as webpack
+const resolveModule = (resolveFn, filePath) => {
+  const extension = moduleFileExtensions.find(extension =>
+    fs.existsSync(resolveFn(`${filePath}.${extension}`))
+  );
+
+  if (extension) {
+    return resolveFn(`${filePath}.${extension}`);
+  }
+
+  return resolveFn(`${filePath}.js`);
+};
+
+// config after eject: we're in ./config/
+module.exports = {
+  dotenv: resolveApp('.env'),
+  appPath: resolveApp('.'),
+  appBuild: resolveApp('build'),
+  appPublic: resolveApp('public'),
+  appHtml: resolveApp('public/index.html'),
+  appIndexJs: resolveModule(resolveApp, 'src/index'),
+  appPackageJson: resolveApp('package.json'),
+  appSrc: resolveApp('src'),
+  appTsConfig: resolveApp('tsconfig.json'),
+  appJsConfig: resolveApp('jsconfig.json'),
+  yarnLockFile: resolveApp('yarn.lock'),
+  testsSetup: resolveModule(resolveApp, 'src/setupTests'),
+  proxySetup: resolveApp('src/setupProxy.js'),
+  appNodeModules: resolveApp('node_modules'),
+  swSrc: resolveModule(resolveApp, 'src/service-worker'),
+  publicUrlOrPath,
+};
+
+
+
+module.exports.moduleFileExtensions = moduleFileExtensions;

config/pnpTs.js

+'use strict';
+
+const { resolveModuleName } = require('ts-pnp');
+
+exports.resolveModuleName = (
+  typescript,
+  moduleName,
+  containingFile,
+  compilerOptions,
+  resolutionHost
+) => {
+  return resolveModuleName(
+    moduleName,
+    containingFile,
+    compilerOptions,
+    resolutionHost,
+    typescript.resolveModuleName
+  );
+};
+
+exports.resolveTypeReferenceDirective = (
+  typescript,
+  moduleName,
+  containingFile,
+  compilerOptions,
+  resolutionHost
+) => {
+  return resolveModuleName(
+    moduleName,
+    containingFile,
+    compilerOptions,
+    resolutionHost,
+    typescript.resolveTypeReferenceDirective
+  );
+};

config/webpackDevServer.config.js

+'use strict';
+
+const fs = require('fs');
+const errorOverlayMiddleware = require('react-dev-utils/errorOverlayMiddleware');
+const evalSourceMapMiddleware = require('react-dev-utils/evalSourceMapMiddleware');
+const noopServiceWorkerMiddleware = require('react-dev-utils/noopServiceWorkerMiddleware');
+const ignoredFiles = require('react-dev-utils/ignoredFiles');
+const redirectServedPath = require('react-dev-utils/redirectServedPathMiddleware');
+const paths = require('./paths');
+const getHttpsConfig = require('./getHttpsConfig');
+
+const host = process.env.HOST || '0.0.0.0';
+const sockHost = process.env.WDS_SOCKET_HOST;
+const sockPath = process.env.WDS_SOCKET_PATH; // default: '/sockjs-node'
+const sockPort = process.env.WDS_SOCKET_PORT;
+
+module.exports = function (proxy, allowedHost) {
+  return {
+    // WebpackDevServer 2.4.3 introduced a security fix that prevents remote
+    // websites from potentially accessing local content through DNS rebinding:
+    // https://github.com/webpack/webpack-dev-server/issues/887
+    // https://medium.com/webpack/webpack-dev-server-middleware-security-issues-1489d950874a
+    // However, it made several existing use cases such as development in cloud
+    // environment or subdomains in development significantly more complicated:
+    // https://github.com/facebook/create-react-app/issues/2271
+    // https://github.com/facebook/create-react-app/issues/2233
+    // While we're investigating better solutions, for now we will take a
+    // compromise. Since our WDS configuration only serves files in the `public`
+    // folder we won't consider accessing them a vulnerability. However, if you
+    // use the `proxy` feature, it gets more dangerous because it can expose
+    // remote code execution vulnerabilities in backends like Django and Rails.
+    // So we will disable the host check normally, but enable it if you have
+    // specified the `proxy` setting. Finally, we let you override it if you
+    // really know what you're doing with a special environment variable.
+    disableHostCheck:
+      !proxy || process.env.DANGEROUSLY_DISABLE_HOST_CHECK === 'true',
+    // Enable gzip compression of generated files.
+    compress: true,
+    // Silence WebpackDevServer's own logs since they're generally not useful.
+    // It will still show compile warnings and errors with this setting.
+    clientLogLevel: 'none',
+    // By default WebpackDevServer serves physical files from current directory
+    // in addition to all the virtual build products that it serves from memory.
+    // This is confusing because those files won’t automatically be available in
+    // production build folder unless we copy them. However, copying the whole
+    // project directory is dangerous because we may expose sensitive files.
+    // Instead, we establish a convention that only files in `public` directory
+    // get served. Our build script will copy `public` into the `build` folder.
+    // In `index.html`, you can get URL of `public` folder with %PUBLIC_URL%:
+    // <link rel="icon" href="%PUBLIC_URL%/favicon.ico">
+    // In JavaScript code, you can access it with `process.env.PUBLIC_URL`.
+    // Note that we only recommend to use `public` folder as an escape hatch
+    // for files like `favicon.ico`, `manifest.json`, and libraries that are
+    // for some reason broken when imported through webpack. If you just want to
+    // use an image, put it in `src` and `import` it from JavaScript instead.
+    contentBase: paths.appPublic,
+    contentBasePublicPath: paths.publicUrlOrPath,
+    // By default files from `contentBase` will not trigger a page reload.
+    watchContentBase: true,
+    // Enable hot reloading server. It will provide WDS_SOCKET_PATH endpoint
+    // for the WebpackDevServer client so it can learn when the files were
+    // updated. The WebpackDevServer client is included as an entry point
+    // in the webpack development configuration. Note that only changes
+    // to CSS are currently hot reloaded. JS changes will refresh the browser.
+    hot: true,
+    // Use 'ws' instead of 'sockjs-node' on server since we're using native
+    // websockets in `webpackHotDevClient`.
+    transportMode: 'ws',
+    // Prevent a WS client from getting injected as we're already including
+    // `webpackHotDevClient`.
+    injectClient: false,
+    // Enable custom sockjs pathname for websocket connection to hot reloading server.
+    // Enable custom sockjs hostname, pathname and port for websocket connection
+    // to hot reloading server.
+    sockHost,
+    sockPath,
+    sockPort,
+    // It is important to tell WebpackDevServer to use the same "publicPath" path as
+    // we specified in the webpack config. When homepage is '.', default to serving
+    // from the root.
+    // remove last slash so user can land on `/test` instead of `/test/`
+    publicPath: paths.publicUrlOrPath.slice(0, -1),
+    // WebpackDevServer is noisy by default so we emit custom message instead
+    // by listening to the compiler events with `compiler.hooks[...].tap` calls above.
+    quiet: true,
+    // Reportedly, this avoids CPU overload on some systems.
+    // https://github.com/facebook/create-react-app/issues/293
+    // src/node_modules is not ignored to support absolute imports
+    // https://github.com/facebook/create-react-app/issues/1065
+    watchOptions: {
+      ignored: ignoredFiles(paths.appSrc),
+    },
+    https: getHttpsConfig(),
+    host,
+    overlay: false,
+    historyApiFallback: {
+      // Paths with dots should still use the history fallback.
+      // See https://github.com/facebook/create-react-app/issues/387.
+      disableDotRule: true,
+      index: paths.publicUrlOrPath,
+    },
+    public: allowedHost,
+    // `proxy` is run between `before` and `after` `webpack-dev-server` hooks
+    proxy,
+    before(app, server) {
+      // Keep `evalSourceMapMiddleware` and `errorOverlayMiddleware`
+      // middlewares before `redirectServedPath` otherwise will not have any effect
+      // This lets us fetch source contents from webpack for the error overlay
+      app.use(evalSourceMapMiddleware(server));
+      // This lets us open files from the runtime error overlay.
+      app.use(errorOverlayMiddleware());
+
+      if (fs.existsSync(paths.proxySetup)) {
+        // This registers user provided middleware for proxy reasons
+        require(paths.proxySetup)(app);
+      }
+    },
+    after(app) {
+      // Redirect to `PUBLIC_URL` or `homepage` from `package.json` if url not match
+      app.use(redirectServedPath(paths.publicUrlOrPath));
+
+      // This service worker file is effectively a 'no-op' that will reset any
+      // previous service worker registered for the same host:port combination.
+      // We do this in development to avoid hitting the production cache if
+      // it used the same host and port.
+      // https://github.com/facebook/create-react-app/issues/2272#issuecomment-302832432
+      app.use(noopServiceWorkerMiddleware(paths.publicUrlOrPath));
+    },
+  };
+};

package.json

@@ -25,8 +25,7 @@
     "test": "craco test",
     "start1": "react-scripts start",
     "build1": "react-scripts build",
-    "test1": "react-scripts test",
-    "eject": "react-scripts eject"
+    "test1": "react-scripts test"
   },
   "eslintConfig": {
     "extends": [

scripts/build.js

+'use strict';
+
+// Do this as the first thing so that any code reading it knows the right env.
+process.env.BABEL_ENV = 'production';
+process.env.NODE_ENV = 'production';
+
+// Makes the script crash on unhandled rejections instead of silently
+// ignoring them. In the future, promise rejections that are not handled will
+// terminate the Node.js process with a non-zero exit code.
+process.on('unhandledRejection', err => {
+  throw err;
+});
+
+// Ensure environment variables are read.
+require('../config/env');
+
+
+const path = require('path');
+const chalk = require('react-dev-utils/chalk');
+const fs = require('fs-extra');
+const bfj = require('bfj');
+const webpack = require('webpack');
+const configFactory = require('../config/webpack.config');
+const paths = require('../config/paths');
+const checkRequiredFiles = require('react-dev-utils/checkRequiredFiles');
+const formatWebpackMessages = require('react-dev-utils/formatWebpackMessages');
+const printHostingInstructions = require('react-dev-utils/printHostingInstructions');
+const FileSizeReporter = require('react-dev-utils/FileSizeReporter');
+const printBuildError = require('react-dev-utils/printBuildError');
+
+const measureFileSizesBeforeBuild =
+  FileSizeReporter.measureFileSizesBeforeBuild;
+const printFileSizesAfterBuild = FileSizeReporter.printFileSizesAfterBuild;
+const useYarn = fs.existsSync(paths.yarnLockFile);
+
+// These sizes are pretty large. We'll warn for bundles exceeding them.
+const WARN_AFTER_BUNDLE_GZIP_SIZE = 512 * 1024;
+const WARN_AFTER_CHUNK_GZIP_SIZE = 1024 * 1024;
+
+const isInteractive = process.stdout.isTTY;
+
+// Warn and crash if required files are missing
+if (!checkRequiredFiles([paths.appHtml, paths.appIndexJs])) {
+  process.exit(1);
+}
+
+const argv = process.argv.slice(2);
+const writeStatsJson = argv.indexOf('--stats') !== -1;
+
+// Generate configuration
+const config = configFactory('production');
+
+// We require that you explicitly set browsers and do not fall back to
+// browserslist defaults.
+const { checkBrowsers } = require('react-dev-utils/browsersHelper');
+checkBrowsers(paths.appPath, isInteractive)
+  .then(() => {
+    // First, read the current file sizes in build directory.
+    // This lets us display how much they changed later.
+    return measureFileSizesBeforeBuild(paths.appBuild);
+  })
+  .then(previousFileSizes => {
+    // Remove all content but keep the directory so that
+    // if you're in it, you don't end up in Trash
+    fs.emptyDirSync(paths.appBuild);
+    // Merge with the public folder
+    copyPublicFolder();
+    // Start the webpack build
+    return build(previousFileSizes);
+  })
+  .then(
+    ({ stats, previousFileSizes, warnings }) => {
+      if (warnings.length) {
+        console.log(chalk.yellow('Compiled with warnings.\n'));
+        console.log(warnings.join('\n\n'));
+        console.log(
+          '\nSearch for the ' +
+            chalk.underline(chalk.yellow('keywords')) +
+            ' to learn more about each warning.'
+        );
+        console.log(
+          'To ignore, add ' +
+            chalk.cyan('// eslint-disable-next-line') +
+            ' to the line before.\n'
+        );
+      } else {
+        console.log(chalk.green('Compiled successfully.\n'));
+      }
+
+      console.log('File sizes after gzip:\n');
+      printFileSizesAfterBuild(
+        stats,
+        previousFileSizes,
+        paths.appBuild,
+        WARN_AFTER_BUNDLE_GZIP_SIZE,
+        WARN_AFTER_CHUNK_GZIP_SIZE
+      );
+      console.log();
+
+      const appPackage = require(paths.appPackageJson);
+      const publicUrl = paths.publicUrlOrPath;
+      const publicPath = config.output.publicPath;
+      const buildFolder = path.relative(process.cwd(), paths.appBuild);
+      printHostingInstructions(
+        appPackage,
+        publicUrl,
+        publicPath,
+        buildFolder,
+        useYarn
+      );
+    },
+    err => {
+      const tscCompileOnError = process.env.TSC_COMPILE_ON_ERROR === 'true';
+      if (tscCompileOnError) {
+        console.log(
+          chalk.yellow(
+            'Compiled with the following type errors (you may want to check these before deploying your app):\n'
+          )
+        );
+        printBuildError(err);
+      } else {
+        console.log(chalk.red('Failed to compile.\n'));
+        printBuildError(err);
+        process.exit(1);
+      }
+    }
+  )
+  .catch(err => {
+    if (err && err.message) {
+      console.log(err.message);
+    }
+    process.exit(1);
+  });
+
+// Create the production build and print the deployment instructions.
+function build(previousFileSizes) {
+  console.log('Creating an optimized production build...');
+
+  const compiler = webpack(config);
+  return new Promise((resolve, reject) => {
+    compiler.run((err, stats) => {
+      let messages;
+      if (err) {
+        if (!err.message) {
+          return reject(err);
+        }
+
+        let errMessage = err.message;
+
+        // Add additional information for postcss errors
+        if (Object.prototype.hasOwnProperty.call(err, 'postcssNode')) {
+          errMessage +=
+            '\nCompileError: Begins at CSS selector ' +
+            err['postcssNode'].selector;
+        }
+
+        messages = formatWebpackMessages({
+          errors: [errMessage],
+          warnings: [],
+        });
+      } else {
+        messages = formatWebpackMessages(
+          stats.toJson({ all: false, warnings: true, errors: true })
+        );
+      }
+      if (messages.errors.length) {
+        // Only keep the first error. Others are often indicative
+        // of the same problem, but confuse the reader with noise.
+        if (messages.errors.length > 1) {
+          messages.errors.length = 1;
+        }
+        return reject(new Error(messages.errors.join('\n\n')));
+      }
+      if (
+        process.env.CI &&
+        (typeof process.env.CI !== 'string' ||
+          process.env.CI.toLowerCase() !== 'false') &&
+        messages.warnings.length
+      ) {
+        console.log(
+          chalk.yellow(
+            '\nTreating warnings as errors because process.env.CI = true.\n' +
+              'Most CI servers set it automatically.\n'
+          )
+        );
+        return reject(new Error(messages.warnings.join('\n\n')));
+      }
+
+      const resolveArgs = {
+        stats,
+        previousFileSizes,
+        warnings: messages.warnings,
+      };
+
+      if (writeStatsJson) {
+        return bfj
+          .write(paths.appBuild + '/bundle-stats.json', stats.toJson())
+          .then(() => resolve(resolveArgs))
+          .catch(error => reject(new Error(error)));
+      }
+
+      return resolve(resolveArgs);
+    });
+  });
+}
+
+function copyPublicFolder() {
+  fs.copySync(paths.appPublic, paths.appBuild, {
+    dereference: true,
+    filter: file => file !== paths.appHtml,
+  });
+}

scripts/start.js

+'use strict';
+
+// Do this as the first thing so that any code reading it knows the right env.
+process.env.BABEL_ENV = 'development';
+process.env.NODE_ENV = 'development';
+
+// Makes the script crash on unhandled rejections instead of silently
+// ignoring them. In the future, promise rejections that are not handled will
+// terminate the Node.js process with a non-zero exit code.
+process.on('unhandledRejection', err => {
+  throw err;
+});
+
+// Ensure environment variables are read.
+require('../config/env');
+
+
+const fs = require('fs');
+const chalk = require('react-dev-utils/chalk');
+const webpack = require('webpack');
+const WebpackDevServer = require('webpack-dev-server');
+const clearConsole = require('react-dev-utils/clearConsole');
+const checkRequiredFiles = require('react-dev-utils/checkRequiredFiles');
+const {
+  choosePort,
+  createCompiler,
+  prepareProxy,
+  prepareUrls,
+} = require('react-dev-utils/WebpackDevServerUtils');
+const openBrowser = require('react-dev-utils/openBrowser');
+const semver = require('semver');
+const paths = require('../config/paths');
+const configFactory = require('../config/webpack.config');
+const createDevServerConfig = require('../config/webpackDevServer.config');
+const getClientEnvironment = require('../config/env');
+const react = require(require.resolve('react', { paths: [paths.appPath] }));
+
+const env = getClientEnvironment(paths.publicUrlOrPath.slice(0, -1));
+const useYarn = fs.existsSync(paths.yarnLockFile);
+const isInteractive = process.stdout.isTTY;
+
+// Warn and crash if required files are missing
+if (!checkRequiredFiles([paths.appHtml, paths.appIndexJs])) {
+  process.exit(1);
+}
+
+// Tools like Cloud9 rely on this.
+const DEFAULT_PORT = parseInt(process.env.PORT, 10) || 3000;
+const HOST = process.env.HOST || '0.0.0.0';
+
+if (process.env.HOST) {
+  console.log(
+    chalk.cyan(
+      `Attempting to bind to HOST environment variable: ${chalk.yellow(
+        chalk.bold(process.env.HOST)
+      )}`
+    )
+  );
+  console.log(
+    `If this was unintentional, check that you haven't mistakenly set it in your shell.`
+  );
+  console.log(
+    `Learn more here: ${chalk.yellow('https://cra.link/advanced-config')}`
+  );
+  console.log();
+}
+
+// We require that you explicitly set browsers and do not fall back to
+// browserslist defaults.
+const { checkBrowsers } = require('react-dev-utils/browsersHelper');
+checkBrowsers(paths.appPath, isInteractive)
+  .then(() => {
+    // We attempt to use the default port but if it is busy, we offer the user to
+    // run on a different port. `choosePort()` Promise resolves to the next free port.
+    return choosePort(HOST, DEFAULT_PORT);
+  })
+  .then(port => {
+    if (port == null) {
+      // We have not found a port.
+      return;
+    }
+
+    const config = configFactory('development');
+    const protocol = process.env.HTTPS === 'true' ? 'https' : 'http';
+    const appName = require(paths.appPackageJson).name;
+
+    const useTypeScript = fs.existsSync(paths.appTsConfig);
+    const tscCompileOnError = process.env.TSC_COMPILE_ON_ERROR === 'true';
+    const urls = prepareUrls(
+      protocol,
+      HOST,
+      port,
+      paths.publicUrlOrPath.slice(0, -1)
+    );
+    const devSocket = {
+      warnings: warnings =>
+        devServer.sockWrite(devServer.sockets, 'warnings', warnings),
+      errors: errors =>
+        devServer.sockWrite(devServer.sockets, 'errors', errors),
+    };
+    // Create a webpack compiler that is configured with custom messages.
+    const compiler = createCompiler({
+      appName,
+      config,
+      devSocket,
+      urls,
+      useYarn,
+      useTypeScript,
+      tscCompileOnError,
+      webpack,
+    });
+    // Load proxy config
+    const proxySetting = require(paths.appPackageJson).proxy;
+    const proxyConfig = prepareProxy(
+      proxySetting,
+      paths.appPublic,
+      paths.publicUrlOrPath
+    );
+    // Serve webpack assets generated by the compiler over a web server.
+    const serverConfig = createDevServerConfig(
+      proxyConfig,
+      urls.lanUrlForConfig
+    );
+    const devServer = new WebpackDevServer(compiler, serverConfig);
+    // Launch WebpackDevServer.
+    devServer.listen(port, HOST, err => {
+      if (err) {
+        return console.log(err);
+      }
+      if (isInteractive) {
+        clearConsole();
+      }
+
+      if (env.raw.FAST_REFRESH && semver.lt(react.version, '16.10.0')) {
+        console.log(
+          chalk.yellow(
+            `Fast Refresh requires React 16.10 or higher. You are using React ${react.version}.`
+          )
+        );
+      }
+
+      console.log(chalk.cyan('Starting the development server...\n'));
+      openBrowser(urls.localUrlForBrowser);
+    });
+
+    ['SIGINT', 'SIGTERM'].forEach(function (sig) {
+      process.on(sig, function () {
+        devServer.close();
+        process.exit();
+      });
+    });
+
+    if (process.env.CI !== 'true') {
+      // Gracefully exit when stdin ends
+      process.stdin.on('end', function () {
+        devServer.close();
+        process.exit();
+      });
+    }
+  })
+  .catch(err => {
+    if (err && err.message) {
+      console.log(err.message);
+    }
+    process.exit(1);
+  });

scripts/test.js

+'use strict';
+
+// Do this as the first thing so that any code reading it knows the right env.
+process.env.BABEL_ENV = 'test';
+process.env.NODE_ENV = 'test';
+process.env.PUBLIC_URL = '';
+
+// Makes the script crash on unhandled rejections instead of silently
+// ignoring them. In the future, promise rejections that are not handled will
+// terminate the Node.js process with a non-zero exit code.
+process.on('unhandledRejection', err => {
+  throw err;
+});
+
+// Ensure environment variables are read.
+require('../config/env');
+
+
+const jest = require('jest');
+const execSync = require('child_process').execSync;
+let argv = process.argv.slice(2);
+
+function isInGitRepository() {
+  try {
+    execSync('git rev-parse --is-inside-work-tree', { stdio: 'ignore' });
+    return true;
+  } catch (e) {
+    return false;
+  }
+}
+
+function isInMercurialRepository() {
+  try {
+    execSync('hg --cwd . root', { stdio: 'ignore' });
+    return true;
+  } catch (e) {
+    return false;
+  }
+}
+
+// Watch unless on CI or explicitly running all tests
+if (
+  !process.env.CI &&
+  argv.indexOf('--watchAll') === -1 &&
+  argv.indexOf('--watchAll=false') === -1
+) {
+  // https://github.com/facebook/create-react-app/issues/5210
+  const hasSourceControl = isInGitRepository() || isInMercurialRepository();
+  argv.push(hasSourceControl ? '--watch' : '--watchAll');
+}
+
+
+jest.run(argv);

src/react-app-env.d.ts

-/// <reference types="react-scripts" />
+/// <reference types="node" />
+/// <reference types="react" />
+/// <reference types="react-dom" />
+
+declare namespace NodeJS {
+  interface ProcessEnv {
+    readonly NODE_ENV: 'development' | 'production' | 'test';
+    readonly PUBLIC_URL: string;
+  }
+}
+
+declare module '*.avif' {
+  const src: string;
+  export default src;
+}
+
+declare module '*.bmp' {
+  const src: string;
+  export default src;
+}
+
+declare module '*.gif' {
+  const src: string;
+  export default src;
+}
+
+declare module '*.jpg' {
+  const src: string;
+  export default src;
+}
+
+declare module '*.jpeg' {
+  const src: string;
+  export default src;
+}
+
+declare module '*.png' {
+  const src: string;
+  export default src;
+}
+
+declare module '*.webp' {
+    const src: string;
+    export default src;
+}
+
+declare module '*.svg' {
+  import * as React from 'react';
+
+  export const ReactComponent: React.FunctionComponent<React.SVGProps<
+    SVGSVGElement
+  > & { title?: string }>;
+
+  const src: string;
+  export default src;
+}
+
+declare module '*.module.css' {
+  const classes: { readonly [key: string]: string };
+  export default classes;
+}
+
+declare module '*.module.scss' {
+  const classes: { readonly [key: string]: string };
+  export default classes;
+}
+
+declare module '*.module.sass' {
+  const classes: { readonly [key: string]: string };
+  export default classes;
+}

yarn.lock

@@ -5268,8 +5268,8 @@ fsevents@^2.1.2, fsevents@~2.1.2:
 
 fsevents@^2.1.3:
   version "2.2.1"
-  resolved "https://registry.yarnpkg.com/fsevents/-/fsevents-2.2.1.tgz#1fb02ded2036a8ac288d507a65962bd87b97628d"
-  integrity sha512-bTLYHSeC0UH/EFXS9KqWnXuOl/wHK5Z/d+ghd5AsFMYN7wIGkUCOJyzy88+wJKkZPGON8u4Z9f6U4FdgURE9qA==
+  resolved "https://registry.npm.taobao.org/fsevents/download/fsevents-2.2.1.tgz?cache=0&sync_timestamp=1604595212408&other_urls=https%3A%2F%2Fregistry.npm.taobao.org%2Ffsevents%2Fdownload%2Ffsevents-2.2.1.tgz#1fb02ded2036a8ac288d507a65962bd87b97628d"
+  integrity sha1-H7At7SA2qKwojVB6ZZYr2HuXYo0=
 
 function-bind@^1.1.1:
   version "1.1.1"
@@ -9654,8 +9654,8 @@ react-refresh@^0.8.3:
 
 react-scripts@4.0.0:
   version "4.0.0"
-  resolved "https://registry.yarnpkg.com/react-scripts/-/react-scripts-4.0.0.tgz#36f3d84ffff708ac0618fd61e71eaaea11c26417"
-  integrity sha512-icJ/ctwV5XwITUOupBP9TUVGdWOqqZ0H08tbJ1kVC5VpNWYzEZ3e/x8axhV15ZXRsixLo27snwQE7B6Zd9J2Tg==
+  resolved "https://registry.npm.taobao.org/react-scripts/download/react-scripts-4.0.0.tgz?cache=0&sync_timestamp=1603464105402&other_urls=https%3A%2F%2Fregistry.npm.taobao.org%2Freact-scripts%2Fdownload%2Freact-scripts-4.0.0.tgz#36f3d84ffff708ac0618fd61e71eaaea11c26417"
+  integrity sha1-NvPYT//3CKwGGP1h5x6q6hHCZBc=
   dependencies:
     "@babel/core" "7.12.3"
     "@pmmmwh/react-refresh-webpack-plugin" "0.4.2"