How to type with typescript a angularfire observable?

Question

I am trying to use angularfire properly and type it. But I always have this error :

 getMessages(): Observable<ChatMessage[]> {
    return this.db.collection('chat').valueChanges();

}

I tried this workaround, but is not clean

 getMessages(): Observable<ChatMessage[]> {
    return <any>this.db.collection('chat').valueChanges();

See if any of the methods in this.db.collection('chat').valueChanges() are generic. My bet is that collection is generic and this.db.collection<ChatMessage>('chat').valueChanges() should work. — Titian Cernicova-Dragomir
– Titian Cernicova-Dragomir, Commented Sep 16, 2018 at 17:31
It was just a guess, based on how such APIs usually work :). The idea is that there is not enough info there to get to the ChatMessage type so you probably have to specify it somewhere, and collection seemed like a logical answer. Anyway, someone seems to have posted an answer with a link :) — Titian Cernicova-Dragomir
– Titian Cernicova-Dragomir, Commented Sep 16, 2018 at 17:35

Gerard Walace · Accepted Answer · 2018-09-16 17:33:59Z

3

You need to use

this.db.collection<ChatMessage>('chat')

As you can see here

answered Sep 16, 2018 at 17:27

Gerard Walace

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Comments

Kevin Püchl · Accepted Answer · 2020-03-24 09:50:34Z

0

If you're using RTDB:

this.db.list<ChatMessage>('chat');

answered Dec 30, 2019 at 15:40

Kevin Püchl

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Giving more details and explanation is always better.