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ViewsFirebase Database V9 Return last item
I have a chat system where a chat contains multiple messages the structure looks like this below:
- messages
- ChatId123
- MesageId123
- MessageId456
I just want to retrieve the last message sent in this case MessageId456 I assume I need to use orderByKey(). The keys are generated using push() how can I correctly query and filter for the last item?
const query = query(ref(db, `messages/ChatId123`), orderByKey())
return query
·
Juan Pablo Isaza
2 answers
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the easiest way would be to add timestamp field in the message object like "SendAt" and orderBy this value :
const q = query(ref(db, `messages/ChatId123`), orderBy("SendAt", "desc"), limit(1));
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Juan Pablo Isaza
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You can use limitToLast to get just the last item(s) from a query:
query(ref(db, `messages/ChatId123`), orderByKey(), limitToLast(1))
For more on this, see the Firebase documentation on filtering data.
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Juan Pablo Isaza
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