module.exports = function (api) { const validEnv = ['development', 'test', 'production']; const currentEnv = api.env(); const isDevelopmentEnv = api.env('development'); const isProductionEnv = api.env('production'); const isTestEnv = api.env('test'); const isWebpackDevServer = process.env.WEBPACK_DEV_SERVER; if (!validEnv.includes(currentEnv)) { throw new Error( 'Please specify a valid `NODE_ENV` or ' + '`BABEL_ENV` environment variables. Valid values are "development", ' + '"test", and "production". Instead, received: ' + JSON.stringify(currentEnv) + '.' ); } return { presets: [ isTestEnv && [ '@babel/preset-env', { targets: { node: 'current' }, modules: 'commonjs' }, '@babel/preset-react' ], (isProductionEnv || isDevelopmentEnv) && [ '@babel/preset-env', { forceAllTransforms: true, useBuiltIns: 'entry', corejs: 3, modules: false, exclude: ['transform-typeof-symbol'] } ], [ '@babel/preset-react', { development: isDevelopmentEnv || isTestEnv, useBuiltIns: true } ], ['@babel/preset-typescript', { allExtensions: true, isTSX: true }] ].filter(Boolean), plugins: [ isWebpackDevServer && 'react-refresh/babel', 'babel-plugin-macros', '@babel/plugin-syntax-dynamic-import', isTestEnv && 'babel-plugin-dynamic-import-node', '@babel/plugin-transform-destructuring', [ '@babel/plugin-proposal-class-properties', { loose: true } ], [ '@babel/plugin-proposal-object-rest-spread', { useBuiltIns: true } ], [ '@babel/plugin-transform-runtime', { helpers: false, regenerator: true, corejs: false } ], [ '@babel/plugin-transform-regenerator', { async: false } ], isProductionEnv && [ 'babel-plugin-transform-react-remove-prop-types', { removeImport: true } ] ].filter(Boolean) }; };