.babelrc.js

const { NODE_ENV, BABEL_ENV } = process.env

const cjs = BABEL_ENV === 'cjs' || NODE_ENV === 'test'
const loose = true

module.exports = {
  presets: [
    [
      '@babel/preset-env',
      {
        loose,
        modules: false,
        forceAllTransforms: true,
        exclude: ['transform-regenerator'],
      },
    ],
  ],
  plugins: [
    cjs && '@babel/plugin-transform-modules-commonjs',
    ['@babel/plugin-proposal-object-rest-spread', { loose }],
    'babel-plugin-annotate-pure-calls',
  ].filter(Boolean),
}