better onDestroy mechanism

[vthinkxie]

current way

  private destroy$ = new Subject();
  ngOnDestroy(): void {
    this.destroy$.next();
    this.destroy$.complete();
  }

better way

extends subject

ref https://stackblitz.com/edit/angular-auto-unsubscribe-service?file=src%2Fapp%2Fhello.component.ts

@Injectable()
export class NgOnDestroy extends Subject<null> implements OnDestroy {
  ngOnDestroy() {
    this.next();
    this.complete();
  }
}

@Component({
  selector: 'hello',
  template: `<h1>Hello {{name}}!</h1>`,
  styles: [`h1 { font-family: Lato; }`],
  providers: [ NgOnDestroy ]
})
export class HelloComponent implements OnInit {
  @Input() name: string;

  constructor(@Self() private ngOnDestroy$: NgOnDestroy) {}

  ngOnInit() {
    this.ngOnDestroy$.subscribe().add(() => console.log('Destroyed!'));
  }
}

extends Obseverable

https://twitter.com/Waterplea/status/1271037735332204544

[Airblader]

This is interesting, but why exactly is it "better" or performance related? It doesn't really save any code, nor changes what actually happens. In fact it creates more runtime overhead by creating more objects.

Another alternative is a OnceSubject which has a single method for next + complete, that would also save a bit of code when used.

[cipchk]

建议作为 import { NgOnDestroy } from 'ng-zorro-antd/core/xxxx' 的一部分。