multi query and pagination with firestore

Check this example App using FireStore with Angular 8 app having pagination

using queries

limit()

orderBy()

startAt()

endBefore()

startAfter()

There has documentation at firebase on Pagination & Query and query data. We have to use the startAt() or startAfter() methods to define the start point for a query. Similarly, use the endAt() or endBefore() methods to define an end point for your query results.

Example: To get all cities with a population >= 1,000,000, ordered by population,

db.collection("cities")
        .orderBy("population")
        .startAt(1000000);

and to get all cities with a population <= 1,000,000, ordered by population,

db.collection("cities")
        .orderBy("population")
        .endAt(1000000);

So pagination should be done using this method like,

// Construct query for first 25 cities, ordered by population
Query first = db.collection("cities")
        .orderBy("population")
        .limit(25);

first.get()
    .addOnSuccessListener(new OnSuccessListener<QuerySnapshot>() {
        @Override
        public void onSuccess(QuerySnapshot documentSnapshots) {
            // ...

            // Get the last visible document
            DocumentSnapshot lastVisible = documentSnapshots.getDocuments()
                    .get(documentSnapshots.size() -1);

            // Construct a new query starting at this document,
            // get the next 25 cities.
            Query next = db.collection("cities")
                    .orderBy("population")
                    .startAfter(lastVisible)
                    .limit(25);

            // Use the query for pagination
            // ...
        }
    });

A Firestore query can only have a single range condition.

From the documentation on queries:

You can combine where() filters with orderBy() and limit().

However, if you have a filter with a range comparison (<, <=, >, >=), your first ordering must be on the same field:

Invalid: Range filter and first orderBy on different fields

citiesRef.where("population", ">", 100000).orderBy("country")