Firebase where query

Question

I have a problem, here is the code:

        const firstName = "rick";

        const users = await db.collection('user');

        if (firstName != undefined) {
            users.where("name", "==", firstName );
        }
        
        const snap = users.get();

why this query return me the whole document with all objects? How to do a query based on where clause that can be null or undefined? Thanks for any help!

Dharmaraj · Accepted Answer · 2021-09-23T18:05:58.770

2

You are not reassigning the users and hence it's fetching whole collection. Try refactoring like this:

let users: firebase.firestore.Query = db.collection('user'); 
//^ let instead of const

if (firstName) { 
  users = users.where("name", "==", firstName );
  // ^^ updating original 'users' value
}
        
const snap = users.get();

edited Sep 23 '21 at 18:05

answered Sep 23 '21 at 17:47

Dharmaraj

47,845
8
52
84

hmm, vscode throw me this: `Type 'Query' is missing the following properties from type 'CollectionReference':` – markWanka Sep 23 '21 at 17:57
on `users` (lefthand) in `if` statement – markWanka Sep 23 '21 at 17:57
@markWanka try adding the query type as in updated answer. CollectionRef seems a subclass of Query as in [this answer](https://stackoverflow.com/questions/60857851/dynamic-where-conditions-with-firestore-and-typescript) – Dharmaraj Sep 23 '21 at 18:06
1

thanks!, it works :) – markWanka Sep 23 '21 at 18:07

Firebase where query

1 Answers1