How to add an OrderBy or Where to a collectionData query

[firepebble]

Hi all,

Still not clear how to do an "orderBy" or a "where" filter in the collection query strings. I'm setting up a service in my app like so:

dbCountries: Observable<any[]>;
public getDBcountries() {
if (!this.dbCountries) {
const readCollection = collection(this.firestore, countryCollectName.collectName);
this.dbCountries = collectionData(readCollection, { idField: 'id' }).pipe(
shareReplay(1)
) as Observable<any[]>;
}
return this.dbCountries;
}

Anyone having any luck?

[jjmhalew]

I had the same issue and finally found the fix myself!

You will have to create one or more constraints, which is a where() for example.
Then you use a query, in which you pass the collection you want to query and the queryConstraints

Example in my code where I used 2 constraints to get orders from a specific date:

    const ordersRef = collection(this.firestore, this.ORDER_COLLECTION_NAME);
    const startDateConstraint = where('date', '>=', date1);
    const endDateConstraint = where('date', '<', date2);
    const ordersByTodayQuery = query(ordersRef, startDateConstraint, endDateConstraint);
    return collectionData(ordersByTodayQuery) as Observable<IOrder[]>;

I hope this will help someone!

[firepebble]

Thanks, here is a version I got working for making my country list to sort:

  // Make a country list service available across all pages
  dbCountries: Observable<any[]>;
  public getDBcountries() {
    if (!this.dbCountries) {
      const readCollection = collection(this.firestore, countryCollectName.collectName);

      const readQuery = query(readCollection, orderBy('countrySimple', 'asc')); // asc or desc

      this.dbCountries = collectionData(readQuery).pipe(
        shareReplay(1)
      ) as Observable<any[]>;
    } // can get the document ids using: readQuery, { idField: 'id' }
    return this.dbCountries;
  }