How can I order by an array element with angular

Question

I have this firebase document, and I want to order by the text field from the first element of the name array, so the official name.

Here is the code I am trying to use, but it's not working:

get(collectionName: string): Observable<T[]> {
    return this.afs.collection(collectionName, ref => {
      let query: CollectionReference | Query = ref;
      query = query.orderBy('text', 'asc').where('name', 'array-contains', 'official');
      return query;
    }).valueChanges() as Observable<T[]>;
}

Cause as I can see you are using commpund queries here (multiple queries in your case 2 queries and that is, orderBy and where) — 50_Seconds _Of_Coding, May 24 '21 at 16:02
To be more specific, your query is getting you the expected result and not ordering or simply not getting any results? I ask this because I believe the query you are trying to make is not possible with Firestore. — Ralemos, May 25 '21 at 12:08
I don't get any results, and I don't even know if I need the where. All I want to do is order by the name[0].text — iwannalearn, May 26 '21 at 08:25

score 1 · Accepted Answer · answered May 26 '21 at 11:37

Querying and sorting by object values inside arrays is not possible with Firestore, at least not directly, as you can see in this community answer:

The array-contains operations checks if an array contains a specific (complete) value. It can't check if an array of objects, contains an item with a specific value for a property.

The same applies to orderBy. So in order to do that you are going to need to change your Firestore structure, a possibility is to create a separate non array field that holds the value where the query should be sorted/queryied by, you can also create a subcollection to represent the values of the array, but that is for you to decide depending on your structure.

How can I order by an array element with angular

1 Answers1