ngOnDestroy(): Cleanup just before Angular destroys the directive/component. Unsubscribe Observables and detach event handlers to avoid memory leaks.
Called just before Angular destroys the directive/component.

一些开发人员说组件属性(类变量)也应该设置为null以避免内存泄漏.这是真的？

export class TestComponent implements OnInit,OnDestroy {

  public name: string;
  constructor() { }

  ngOnInit() {
    this.name = 'John';
  }

  ngOnDestroy() {
   // is this code really necessary.
   this.name = null;
  }

}