module.exports = { presets: [ '@babel/preset-react', ], env: { test: { presets: [ [ '@babel/preset-env', { modules: 'commonjs', targets: { node: true, }, }, ], ], }, // src/index.js ==> lib/index.js commonjs: { presets: [ [ '@babel/preset-env', { loose: true, modules: 'commonjs' }, ], ], }, // src/index.js ==> es/index.js es: { presets: [ [ '@babel/preset-env', { loose: true, targets: { esmodules: true, }, }, ], ], }, // src/index.js ==> dist/index.js rollup: { presets: [ [ '@babel/preset-env', { modules: false, loose: true, targets: '> 0.25%, not dead', }, ], ], }, }, };