Next.js supports IE11 and all modern browsers (Edge, Firefox, Chrome, Safari, Opera, et al) with no required configuration.
We transparently inject polyfills required for IE11 compatibility. In addition, we also inject widely used polyfills, including:
whatwg-fetch and unfetch.url package (Node.js API).object-assign, object.assign, and core-js/object/assign.If any of your dependencies includes these polyfills, they’ll be eliminated automatically from the production build to avoid duplication.
In addition, to reduce bundle size, Next.js will only load these polyfills for browsers that require them. The majority of the web traffic globally will not download these polyfills.
In addition to fetch() on the client side, Next.js polyfills fetch() in the Node.js environment. You can use fetch() on your server code (such as getStaticProps) without using polyfills such as isomorphic-unfetch or node-fetch.
If your own code or any external npm dependencies require features not supported by your target browsers, you need to add polyfills yourself.
In this case, you should add a top-level import for the specific polyfill you need in your Custom <App> or the individual component.
Next.js allows you to use the latest JavaScript features out of the box. In addition to ES6 features, Next.js also supports:
import() (ES2020)Next.js has built-in TypeScript support. Learn more here.
You can customize babel configuration. Learn more here.