Firestore pagination - Is there any query compatible with firebase's limitToLast?

Question

Is there a way to implement back pagination with firestore? I am struggling to implement pagination with firestore, and there are limited firestore queries for it. Forward p

Answer 1

Yes. Building upon Frank's answer...

Have something like this in your query...

    if (this.next) {
      // if next, orderBy field descending, start after last field
      q.orderBy('field', 'desc');
      q.startAfter(this.marker);
    } else if (this.prev) {
      // if prev, orderBy field ascending, start after first field
      q.orderBy('field', 'asc');
      q.startAfter(this.marker);
    } else {
      // otherwise just display first page results normally
      q.orderBy('field', 'desc');
    }
    q.limit(this.pageSize);

and then reverse it when you get the query...

    this.testsCollection
            .valueChanges({ idField: 'id' })
            .pipe(
              tap(results => {
                if (this.prev) {
                  // if previous, need to reverse the results...
                  results.reverse();
                }
              })
            )