next.js/test/integration/repeated-slashes/app/pages/invalid.js

import Link from 'next/link'

if (typeof window !== 'undefined') {
  window.caughtErrors = []
  const origError = window.console.error

  window.console.error = function (...args) {
    window.caughtErrors.push(args.join(' '))
    return origError(...args)
  }
}

export default function Invalid() {
  return (
    <>
      <p id="invalid">invalid page</p>
      <Link href="/another" as="//google.com" id="page-with-as-slashes">
        to /another as //google.com
      </Link>
      <br />

      <Link href="//google.com" id="href-with-slashes">
        to //google.com
      </Link>
      <br />

      <Link href="//google.com?hello=1" id="href-with-slashes-query">
        to //google.com?hello=1
      </Link>
      <br />

      <Link href="//google.com#hello" id="href-with-slashes-hash">
        to //google.com#hello
      </Link>
      <br />

      <Link href="/another" as="\/\/google.com" id="page-with-as-backslashes">
        to /another as \\/\\/google.com
      </Link>
      <br />

      <Link href="\/\/google.com" id="href-with-backslashes">
        to \\/\\/google.com
      </Link>
      <br />

      <Link href="\/\/google.com?hello=1" id="href-with-backslashes-query">
        to \\/\\/google.com?hello=1
      </Link>
      <br />

      <Link href="\/\/google.com#hello" id="href-with-backslashes-hash">
        to \\/\\/google.com#hello
      </Link>
      <br />
    </>
  )
}