I have a Firestore onSnapshot listener listening to changes on a document but I cant seem to understand how it works if I set it in the state like below:
constructor(props) {
super(props);
this.fetchChatsListener = null;
}
and this is how I set it:
this.fetchChatsListener = firestore().collection('chats').doc(documentSnapshot.id).collection('messages').where('created', '>=', currenttime);
this.state.sent_message_id != '' ? this.fetchChatsListener.where(firebase.firestore.FieldPath.documentId(), '!=', this.state.sent_message_id) : ''
this.fetchChatsListener.orderBy('created', 'desc')
.onSnapshot({
error: (e) => console.error(e),
next: (querySnapshot_) => {
querySnapshot_.docChanges().forEach(change => {
this.state.dataSource.push({
...change.doc.data(),
key: change.doc.id,
});
});
this.setState({
chatEntered: true,
dataSource: this.state.dataSource,
refreshingMessages: false,
current_chat_id: documentSnapshot.id
});
},
});
I call this function to unsubscribe from it:
unsubscribe_chats_listener() {
this.fetchChatsListener;
this.fetchChatsListener = null;
}
but unfortunately it does not unsubscribe because I keep receiving new changes.
UPDATE
when I try to unsubscribe using:
this.fetchChatsListener();
it fails with this error:
TypeError: this.fetchChatsListener is not a function
The OP code only mentions the unsubscribe function, it needs to invoke it.
unsubscribe_chats_listener() {
this.fetchChatsListener(); // note the parens, causing invocation
this.fetchChatsListener = null;
}
EDIT
this.fetchChatsListener is being initialized to a query. Query's aren't unsubscribe functions.
this.fetchChatsListener = firestore().collection('chats') // a collection ref
.doc(documentSnapshot.id) // a doc ref
.collection('messages') // a collection ref
.where('created', '>=', currenttime); // a query
onSnapshot() returns the unsubscribe function, so set the property there...
let query = firestore().collection('chats')
.doc(documentSnapshot.id)
.collection('messages')
.where('created', '>=', currenttime);
this.state.sent_message_id != '' ? query.fetchChatsListener.where(firebase.firestore.FieldPath.documentId(), '!=', this.state.sent_message_id) : ''
query.orderBy('created', 'desc')
this.fetchChatsListener = query.onSnapshot({ // an unsubscribe function
error: (e) => console.error(e),
next: (querySnapshot_) => {
// ...