Undefined value from local storage promise. Ionic 2+ / Angular 4.3

Question

I'm able to get the value for the token after logging in because I'm passing in the values for the username and password from a function. On the next page, I'm not passing in those values. Which makes sense as to why I'm getting null - this was when I wasn't wrapping the token returns in the promise. When I wrap the token values in the promise as viewed below, I get this error ERROR TypeError: Cannot read property 'then' of undefined, the token is undefined This is because I havn't logged in with the user credentials I need to generate the token, therefore it's not present or undefined. How would I go about calling the function until the user has logged in. Assuming I won't get null back when I make the call to the second page because like I mentioned above, I wrapped my storage promise returns. Thanks!

Auth.ts

login(userName: string, password: string, route: string = null): any {
    this.logout(false);

    this.doLogin(userName, password)
      .subscribe(response => {
        let token:string = JSON.stringify(response.access_token);
        this.storage.set('token', token);

      });
  }

getToken() :any{
  this.storage.get('token').then((val) => {
        this.accessToken = val;

         if(this.accessToken == null){
              return '0'
         }
            else{
                return "Bearer " + this.accessToken.replace(/["]+/g, '')
            }
    })
}

component.ts

login(){
this.authService.login(this.account.username, this.account.password)
}

Interceptor.ts

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


        let access = this.auth.getToken()

        const authReq = req.clone({
                setHeaders: {
                Authorization: access
                }
        });

    return next.handle(authReq)
  }

Thanks!

Answer 1

Return statement inside the promise method won't work. The storage.get() is a promise which is an async function so value return will not work here. You either need to pass a callback function to the getToken method and invoke it inside the then() function or has to write the intercept logic inside then() function of get method in Interceptor.ts.