Patience is key: Techniques for waiting on service responses in Angular 2

Here is the code snippet I have been working on:

canActivate(route: ActivatedRouteSnapshot, state: RouterStateSnapshot): boolean {
    let isAuthenticated: boolean = false
    this.authServiceLocal.isAuthenticated().then(response => isAuthenticated = response)

    if(isAuthenticated){
      return true
    }

    // If not logged in, redirect to login page with the return url
    this.router.navigate(['/login'], { queryParams: { returnUrl: state.url }});
    return false

  }

I am trying to ensure that my code waits for the response from the service before checking the value of isAuthenticated. The server is providing the expected true and false values, so the issue seems to be related to the async nature of the call.

Answer №1

If you want to proceed once the data is available, simply wait for the response before executing the operation. Update your code as shown below:

 canActivate(route: ActivatedRouteSnapshot, state: RouterStateSnapshot): Promise<any> {
        let isAuthenticated: boolean = false;
        let result = new EventEmitter<boolean>();
        return this.authServiceLocal.isAuthenticated().then(response => {isAuthenticated = response;
    if(isAuthenticated){

        }
        else {
             this.router.navigate(['/login'], { queryParams: { returnUrl: state.url }});
        result.emit(false);
         result.complete();

        }

        // Redirect to login page if not logged in

    })
    return result;
      }

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