/** * Copyright (c) 2015-present, Facebook, Inc. * * This source code is licensed under the MIT license found in the * LICENSE file in the root directory of this source tree. */ 'use strict'; const path = require('path'); const validateBoolOption = (name, value, defaultValue) => { if (typeof value === 'undefined') { value = defaultValue; } if (typeof value !== 'boolean') { throw new Error(`Preset react-app: '${name}' option must be a boolean.`); } return value; }; module.exports = function (api, opts, env) { if (!opts) { opts = {}; } var isEnvDevelopment = env === 'development'; var isEnvProduction = env === 'production'; var isEnvTest = env === 'test'; var useESModules = validateBoolOption( 'useESModules', opts.useESModules, isEnvDevelopment || isEnvProduction ); var isFlowEnabled = validateBoolOption('flow', opts.flow, true); var isTypeScriptEnabled = validateBoolOption( 'typescript', opts.typescript, true ); var areHelpersEnabled = validateBoolOption('helpers', opts.helpers, true); var useAbsoluteRuntime = validateBoolOption( 'absoluteRuntime', opts.absoluteRuntime, true ); var absoluteRuntimePath = undefined; if (useAbsoluteRuntime) { absoluteRuntimePath = path.dirname( require.resolve('@babel/runtime/package.json') ); } if (!isEnvDevelopment && !isEnvProduction && !isEnvTest) { throw new Error( 'Using `babel-preset-react-app` requires that you specify `NODE_ENV` or ' + '`BABEL_ENV` environment variables. Valid values are "development", ' + '"test", and "production". Instead, received: ' + JSON.stringify(env) + '.' ); } return { presets: [ isEnvTest && [ // ES features necessary for user's Node version require('@babel/preset-env').default, { targets: { node: 'current', }, }, ], (isEnvProduction || isEnvDevelopment) && [ // Latest stable ECMAScript features require('@babel/preset-env').default, { // Allow importing core-js in entrypoint and use browserlist to select polyfills useBuiltIns: 'entry', // Set the corejs version we are using to avoid warnings in console corejs: 3, // Exclude transforms that make all code slower exclude: ['transform-typeof-symbol'], }, ], [ require('@babel/preset-react').default, { // Adds component stack to warning messages // Adds __self attribute to JSX which React will use for some warnings development: isEnvDevelopment || isEnvTest, // Will use the native built-in instead of trying to polyfill // behavior for any plugins that require one. ...(opts.runtime !== 'automatic' ? { useBuiltIns: true } : {}), runtime: opts.runtime || 'classic', }, ], isTypeScriptEnabled && [require('@babel/preset-typescript').default], ].filter(Boolean), plugins: [ // Strip flow types before any other transform, emulating the behavior // order as-if the browser supported all of the succeeding features // https://github.com/facebook/create-react-app/pull/5182 // We will conditionally enable this plugin below in overrides as it clashes with // @babel/plugin-proposal-decorators when using TypeScript. // https://github.com/facebook/create-react-app/issues/5741 isFlowEnabled && [ require('@babel/plugin-transform-flow-strip-types').default, false, ], // Experimental macros support. Will be documented after it's had some time // in the wild. require('babel-plugin-macros'), // Disabled as it's handled automatically by preset-env, and `selectiveLoose` isn't // yet merged into babel: https://github.com/babel/babel/pull/9486 // Related: https://github.com/facebook/create-react-app/pull/8215 // [ // require('@babel/plugin-transform-destructuring').default, // { // // Use loose mode for performance: // // https://github.com/facebook/create-react-app/issues/5602 // loose: false, // selectiveLoose: [ // 'useState', // 'useEffect', // 'useContext', // 'useReducer', // 'useCallback', // 'useMemo', // 'useRef', // 'useImperativeHandle', // 'useLayoutEffect', // 'useDebugValue', // ], // }, // ], // Turn on legacy decorators for TypeScript files isTypeScriptEnabled && [ require('@babel/plugin-proposal-decorators').default, false, ], // class { handleClick = () => { } } // Enable loose mode to use assignment instead of defineProperty // See discussion in https://github.com/facebook/create-react-app/issues/4263 // Note: // 'loose' mode configuration must be the same for // * @babel/plugin-proposal-class-properties // * @babel/plugin-proposal-private-methods // * @babel/plugin-proposal-private-property-in-object // (when they are enabled) [ require('@babel/plugin-proposal-class-properties').default, { loose: true, }, ], [ require('@babel/plugin-proposal-private-methods').default, { loose: true, }, ], [ require('@babel/plugin-proposal-private-property-in-object').default, { loose: true, }, ], // Adds Numeric Separators require('@babel/plugin-proposal-numeric-separator').default, // Polyfills the runtime needed for async/await, generators, and friends // https://babeljs.io/docs/en/babel-plugin-transform-runtime [ require('@babel/plugin-transform-runtime').default, { corejs: false, helpers: areHelpersEnabled, // By default, babel assumes babel/runtime version 7.0.0-beta.0, // explicitly resolving to match the provided helper functions. // https://github.com/babel/babel/issues/10261 version: require('@babel/runtime/package.json').version, regenerator: true, // https://babeljs.io/docs/en/babel-plugin-transform-runtime#useesmodules // We should turn this on once the lowest version of Node LTS // supports ES Modules. useESModules, // Undocumented option that lets us encapsulate our runtime, ensuring // the correct version is used // https://github.com/babel/babel/blob/090c364a90fe73d36a30707fc612ce037bdbbb24/packages/babel-plugin-transform-runtime/src/index.js#L35-L42 absoluteRuntime: absoluteRuntimePath, }, ], isEnvProduction && [ // Remove PropTypes from production build require('babel-plugin-transform-react-remove-prop-types').default, { removeImport: true, }, ], // Optional chaining and nullish coalescing are supported in @babel/preset-env, // but not yet supported in webpack due to support missing from acorn. // These can be removed once webpack has support. // See https://github.com/facebook/create-react-app/issues/8445#issuecomment-588512250 require('@babel/plugin-proposal-optional-chaining').default, require('@babel/plugin-proposal-nullish-coalescing-operator').default, ].filter(Boolean), overrides: [ isFlowEnabled && { exclude: /\.tsx?$/, plugins: [require('@babel/plugin-transform-flow-strip-types').default], }, isTypeScriptEnabled && { test: /\.tsx?$/, plugins: [ [ require('@babel/plugin-proposal-decorators').default, { legacy: true }, ], ], }, ].filter(Boolean), }; };