在 componentWillUnmount 中需要取消订阅 Firestore/React [英] Firestore / React is unsubscribe necessary in componentWillUnmount

问题描述

我有一个位于特定路线的组件:

I have a component that is at a particular route:

<Route path='/route-path' component={MyComponent} /> 

在这个组件中，我所有的 firestore 监听器都是在 componentDidMount 中创建的，如下所示:

In this component all of my firestore listeners are created in componentDidMount like so:

componentDidMount() {
   var unsubscribe = db.collection(name)
       .where("query", "==", false)
       .onSnapshot((querySnapshot) => {
          // do something
       })
}

如果路由发生变化，是否需要取消订阅此侦听器?类似的东西:

Is it necessary to unsubscribe this listener if the route changes? Something like:

componentWillUnmount() {
  unsusbscribe() // from componentDidMount
}

或者这是由路由更改自动处理的，即 websocket 关闭连接?

or is this handled automatically by route changes, i.e. the websocket closes the connection?

推荐答案

Firestore SDK 没有关于 ReactJS 和/或其生命周期事件的隐含知识.

The Firestore SDK has no implicit knowledge about ReactJS and/or its lifecycle events.

您需要使用自己的代码取消订阅.它不是自动完成的.

You'll need to unsubscribe in your own code. It is not done automatically.

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