.babelrc.js

const isTest = String(process.env.NODE_ENV) === 'test';
const isProd = String(process.env.NODE_ENV) === 'production';

module.exports = {
  presets: [
    ['@babel/preset-env', {modules: isTest ? 'commonjs' : false}],
    '@babel/preset-react',
  ],
  plugins: [
    '@babel/plugin-proposal-class-properties',
    '@babel/plugin-proposal-object-rest-spread',
  ].filter(Boolean),
};