Location.subscribe()泄漏

Question

我使用Location.subscribe()来检测"back“按钮。https://angular.io/docs/ts/latest/api/common/index/Location-class.html

export class PathLocationComponent {
  location: Location;
  constructor(location: Location) { 
     location.subscribe(val => console.log(val))//output popstate
  }
}

但是，当我重复按“后退”和“向前”按钮时，日志的数量会增加。我认为Locaion.subscribe()在漏水。但是我不知道如何发布它，因为Location类没有取消订阅()。

如何释放Location.subscribe()或防止泄漏？

我想使用PlatformLocation.onPopState()。https://angular.io/docs/ts/latest/api/common/index/PlatformLocation-class.html

但是，文档说明如下

This class should not be used directly by an application developer. Instead, use Location.

Answer 1

你可以试试这个：

import {Subscription} from 'rxjs/Subscription';

export class PathLocationComponent implements OnDestroy {
location: Location;
private subscription: Subscription;

      constructor(location: Location) {
        this.subscription = location.subscribe(val => console.log(val))//output popstate
      }

     ngOnDestroy(): void {
        this.subscription.unsubscribe();
     }
}