babel.config.js

module.exports = function (api) {
  var validEnv = ['development', 'test', 'production'];
  var currentEnv = api.env();
  var isDevelopmentEnv = api.env('development');
  var isProductionEnv = api.env('production');
  var isTestEnv = api.env('test');

  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: ['@babel/preset-env', '@babel/preset-react'],
    // presets: [
    //   isTestEnv && [
    //     '@babel/preset-env',
    //     {
    //       targets: {
    //         node: 'current',
    //       },
    //     },
    //   ],
    //   (isProductionEnv || isDevelopmentEnv) && [
    //     '@babel/preset-env',
    //     {
    //       forceAllTransforms: true,
    //       useBuiltIns: 'entry',
    //       corejs: 3,
    //       modules: false,
    //       exclude: ['transform-typeof-symbol'],
    //     },
    //   ]
    // ].filter(Boolean),
    plugins: [
      'babel-plugin-macros',
      '@babel/plugin-syntax-jsx',
      '@babel/plugin-syntax-dynamic-import',
      isTestEnv && 'babel-plugin-dynamic-import-node',
      '@babel/plugin-transform-destructuring',
      [
        '@babel/plugin-proposal-class-properties',
        {
          // loose: true,
          loose: false,
        },
      ],
      [
        '@babel/plugin-proposal-object-rest-spread',
        {
          useBuiltIns: true,
        },
      ],
      [
        '@babel/plugin-transform-runtime',
        {
          helpers: false,
        },
      ],
      [
        '@babel/plugin-transform-regenerator',
        {
          async: false,
        },
      ],
    ].filter(Boolean),
  };
};