Is it correct way to return from method with subscription inside (Angular)-CodePudding

Is it correct way to return value like in method below?

  private canView(permission: string, resource: string): boolean {
    let result: boolean;

    this.accessChecker.isGranted(permission, resource)
      .pipe(
        take(1)
      )
      .subscribe(
        granted => {
          result = granted;
        }
      );

    return result;
  }

Can I have a situation when result returned before it value will be set in the subscription (for as i know subcribe is asynchronous)? If yes what is the correct way?

CodePudding user response：

are you using this to create boolean for different canView permissions? If so you can just turn those booleans into Observables.

canViewElement1$ = this.canView('element1', 'res1');
canViewElement2$ = this.canView('element2', 'res2');

private canView(permission: string, resource: string): Observable<boolean> {
    return this.accessChecker.isGranted(permission, resource);
}

on the template, if you use it for ngIf, call it with async pipe. you won't have to worry about unsubscribing or take(1) this way:

<div *ngIf="canViewElement1$ | async">
...
</div>

CodePudding user response：

Result might not have the value from the subscription in that point of time

CodePudding user response：

You may want to make canView as an async function, convert the Observable returned by isGranted to promise using toPromise(), then await for the result

  private async canView(permission: string, resource: string): boolean {
    let result: boolean = await this.accessChecker.isGranted(permission, resource)
      .pipe(
        take(1)
      ).toPromise();
    return result;
  }