basePath: urls in Router events include basePath

[Janpot]

Bug report

Describe the bug

Been picking apart the router logic a bit while working on #14827 and noticed that urls that are emitted in router events include the basepath.

Additionally, searching the test folder, there isn't a single test containing "routeChangeStart". It seems like these events are not covered by any tests.

To Reproduce

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

1. configure a basePath
2. add an pages/_app.js like:

   import { useEffect } from 'react'
   import { useRouter } from 'next/router'
   
   export default function MyApp({ Component, pageProps }) {
     const router = useRouter()
   
     useEffect(() => {
       const handleRouteChange = (url) => console.log('App is changing to: ', url)
       router.events.on('routeChangeStart', handleRouteChange)
       return () => router.events.off('routeChangeStart', handleRouteChange)
     }, [])
   
     return <Component {...pageProps} />
   }

3. navigate links in your app and observe the console

Expected behavior

urls don't contain the basepath

[timneutkens]

urls don't contain the basepath

I think this is needed because the events are generally used to track navigations in analytics services like Google Analytics.

[balazsorban44]

This issue has been automatically locked due to no recent activity. If you are running into a similar issue, please create a new issue with the steps to reproduce. Thank you.