babel.config.js

module.exports = function config(api) {
  api.cache(false);
  return {
    env: {
      development: {
        presets: [
          [
            '@babel/preset-env',
            {
              modules: false,
              useBuiltIns: 'entry',
              corejs: 2,
              debug: true,
            },
          ],
          '@babel/preset-react',
        ],
        plugins: [
          '@babel/plugin-syntax-dynamic-import',
          '@babel/plugin-transform-runtime',
          '@babel/proposal-class-properties',
        ],
      },
      test: {
        presets: [['@babel/preset-env'], '@babel/preset-react'],
        plugins: [
          '@babel/plugin-syntax-dynamic-import',
          '@babel/plugin-transform-runtime',
          '@babel/proposal-class-properties',
        ],
      },
      production: {
        presets: [
          [
            '@babel/preset-env',
            {
              modules: false,
              targets: {
                browsers: [
                  'last 2 versions',
                  'safari >= 7',
                  'not ie < 9', // React doesn't support IE8 anyway
                ],
              },
              useBuiltIns: 'entry',
              corejs: 2,
            },
          ],
          '@babel/preset-react',
        ],
        plugins: [
          '@babel/plugin-syntax-dynamic-import',
          '@babel/plugin-transform-runtime',
          '@babel/proposal-class-properties',
        ],
      },
    },
  };
};