Wrong root route redirectTo value after changing language in the URL

[JakubNiedzialkowski]

Description

After changing language code in the URL the root route's redirectTo value is set incorrectly to the previously used value. This results in problems with triggering router.navigate(['/'])

The actual value of the route object:

{ path: "", redirectTo: "fr", pathMatch: "full" }

Desired value of the route object after changing language in the URL:

{ path: "", redirectTo: "en", pathMatch: "full" }

Reproducing the issue

I used the demo app included on the master branch to reproduce the issue. Inside app.component.ts I added a simple console.log() printing out router config like:

    constructor(private localize: LocalizeRouterService, private router: Router) { }

    ngOnInit() {
      console.log(this.router.config);
      (...)
     }

Steps to reproduce

1. Set up the demo app included in project's master branch
2. Launch the app
3. In browser address bar change language code from /en/ -> /fr/ or /fr/ -> /en/
   

Possible solution

I believe the issue is caused by the following piece of code inside localize-router.parser.ts:

   if (this.settings.alwaysSetPrefix) {
      const baseRoute = { path: '', redirectTo: this.defaultLang, pathMatch: 'full' };
      (...)

Since this.defaultLang doesn't take locationLang into consideration. The likely solution would be to change this bit of code to:

const baseRoute = { path: '', redirectTo: selectedLanguage, pathMatch: 'full' };

I'd appreciate any feedback in case I got something wrong in this whole testing problem :)