module.exports = 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');

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',
      {
        modules: 'commonjs',
        targets: {
          node: 'current'
        }
      }
    ],
    (isProductionEnv || isDevelopmentEnv) && [
      '@babel/preset-env',
      {
        forceAllTransforms: true,
        useBuiltIns: 'entry',
        modules: false,
        exclude: ['transform-typeof-symbol']
      }
    ],
    '@babel/preset-react'
  ].filter(Boolean),
  plugins: [
    '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
      }
    ],
    [
      '@babel/plugin-transform-regenerator',
      {
        async: false
      }
    ]
  ].filter(Boolean)
};

};