Angular Basic Token headers characters error UTF8

Question

I am creating a basic token forthe process in angular. I am sendind this token in the headers section.But I get an error when I use characters like 'işğüç' in the name or password. I think it is releated to charset UTF 8 my error is.

return this.http.get<any>(apiHost + '/login',
      {
        headers: {
          Authorization: this.createBasicAuthToken(name, password)
        },
      },
    ).pipe(map(response => {...}



createBasicAuthToken(name: String, password: String) {
    return 'Basic ' + btoa(name+ ":" + password);
  }


export class HttpInterceptorService implements HttpInterceptor {

constructor(private authenticationService: AuthenticationService) { }

intercept(req: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {


    if (this.authenticationService.isUserLoggedIn() && req.url.indexOf('login') === -1) {
        const authReq = req.clone({
            headers: new HttpHeaders({
                'Authorization': `Basic ${window.btoa(this.authenticationService.getLoggedInUserName() + ":" + this.authenticationService.getLoggedInPassword())}`,
            })
        });

      
        return next.handle(authReq);
    }
    else {
        return next.handle(req);
    }
}