订阅可观察的输入

本文介绍了订阅可观察的输入的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

是否可以订阅@Input的Observable?

例如:

export class MyComponent implements OnInit { @Input() results: Observable<string[]>; constructor() { this.results.subscribe(value => ...); } }

在此示例中，我无法订阅可观察对象，因为它是null ...

In this example I can't subscribe to the observable because it is null...

推荐答案

您应该实现OnChanges并在输入更改时订阅.

You should implement OnChanges and subscribe to the input when it changes.

export class MyComponent implements OnChanges { @Input() results: Observable<string[]>; constructor() { } ngOnChanges(changes){ if(changes["results"] && this.results){ this.results.subscribe(value => ...); } } }

这将使您可以在Observable可用时进行订阅，并在Observable参考发生更改时重新订阅.您可能需要根据用例考虑取消订阅旧实例.

This will allow you to subscribe to the Observable once it is available and re-subscribe to it anytime that the Observable reference changes. You may need to consider unsubscribing from old instance depending on your use-case.