The basePath is repeated twice in URL with query params

Bug report

Describe the bug

The basePath is repeated twice in URL when we add query parameters. Say we have set basePath: '/base' in next.config.js, if we enter the /base?foo=bar, it changes to the /base/base?foo=bar.

To Reproduce

Steps to reproduce the behavior, please provide code snippets or a repository:

1. Run the https://repl.it/@theshem/NextBasePathWithQueryParams
2. Navigate to https://nextbasepathwithqueryparams.theshem.repl.co/base?foo=bar

Expected behavior

The URL should remain unchanged. I.e. /base?foo=bar.

Screenshots

System information

• OS: macOS 10.14.5
• Browser (if applies) Chrome 85
• Version of Next.js: 9.5.3
• Version of Node.js: 12.x

[jnv]

Well, since the PR with a fix didn’t get any attention so far, I have implemented an ugly workaround. Just call this hook in you index page and it should get the work done; I lose hash part of URL if also query string is present, but other than that it seems to get the job done:

import {useRouter} from 'next/router'

export function useBasepathFix(): void {
  const {basePath} = useRouter()
  if (typeof window === 'undefined') {
    return
  }
  if (window.location.pathname === basePath + basePath) {
    const fixedUrl = basePath + window.location.search + window.location.hash
    const newState = {
      ...window.history.state,
      as: fixedUrl,
    }
    window.history.replaceState(newState, undefined, fixedUrl)
  }
}

(Edit: Removed interpolation, replicates stored history state)

[indotek68]

Has this been fixed? I’m not seeing it in the latest versions.