Firestore / React is unsubscribe necessary in componentWillUnmount

问题

I have a component that is at a particular route:

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

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
       })
}

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

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

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

回答1:

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

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

来源：https://stackoverflow.com/questions/49868757/firestore-react-is-unsubscribe-necessary-in-componentwillunmount