Question

1

Firestore unsubscribe to updates

rated 0 times [ 8] [ 7] / answers: 1 / hits: 18485 / 6 Years ago, mon, november 5, 2018, 12:00:00

I am following this Google Cloud Firestore example on YouTube and getting real time updates successfully. However, I don't know how to unsubscribe to updates because it's not explained in the video. I read the documentation to create an unsubscribe() function but it doesn't work for me.

	getRealtimeUpdates = function(document) {

		firestore.collection(collection_name)

			.onSnapshot(function(querySnapshot) {

			querySnapshot.forEach(function(doc) {

				if (doc && doc.exists) {

					const myData = doc.data();

					// DO SOMETHING

				}

			});

		});

	}

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elaine

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3 Years ago

answered 6 Years ago tobyl · Accepted Answer

The firestore.collection().onSnapshot() function returns a unsubscribe function. Just call it and you should be guchi.

You can also find another example here: How to remove listener for DocumentSnapshot events (Google Cloud FireStore)

Here is a snippet I created that should work:

let unsubscribe;



getRealtimeUpdates = function(document) {

		unsubscribe = firestore.collection(collection_name)

			.onSnapshot(function(querySnapshot) {

			querySnapshot.forEach(function(doc) {

				if (doc && doc.exists) {

					const myData = doc.data();

					// DO SOMETHING

				}

			});

		});

	}

  

  // unsubscribe:

  

  unsubscribe();

Path to the corresponding Firebase Documentation:

https://firebase.google.com/docs/reference/js/firebase.firestore.CollectionReference#onSnapshot

Returns
An unsubscribe function that can be called to cancel the snapshot listener.