// `.babelrc` is not loaded by babel-loader for files under node_modules, but `babel.config.js` is module.exports = { env: { test: { plugins: ['babel-plugin-transform-es2015-modules-commonjs'], }, }, presets: [ [ '@babel/preset-env', { modules: false, targets: { esmodules: true, }, exclude: [ '@babel/plugin-transform-async-to-generator', '@babel/plugin-proposal-object-rest-spread', ], }, ], '@babel/preset-typescript', '@babel/preset-react', ], plugins: ['@babel/plugin-proposal-optional-chaining', '@babel/plugin-proposal-class-properties'], }