This question is similar to Is Nuxt.js (not pure Vue) check, but about React/Next, not Vue/Nuxt.

So, is there a way to check is Next.js is being used?
Where I can get the constant similar to __IS_NEXT_JS__ or function for checking for the Next.js?

import { BrowserRouter as Router, Route as ReactLink } from 'react-router-dom';
import { Link as ReactLink } from 'react-router-dom';
import NextLink from 'next/link';


// ....

{
  __IS_NEXT_JS__ ? // Warning: this constant is hypothetical
     <ReactLink href="/">
       <a>Home</a>
     </ReactLink>
     <NextLink href="/">
       <a>Home</a>
     </NextLink>
}

This is actual for UI/UX frameworks where it is unknown at advance, will be this framework used with Next.js or pure React.