K.10 Paginate with Query Cursors

Paginate Data with Query Cursors

With query cursors in Cloud Firestore, you can split data returned by a query into batches according to the parameters you define in your query.

Query cursors define the start and end points for a query, allowing you to:

• Return a subset of the data.
• Paginate query results.

However, to define a specific range for a query, you should use the where() method described in Simple Queries.

Add a simple cursor to a query

Use the startAt() or startAfter() methods to define the start point for a query. The startAt() method includes the start point, while the startAfter() method excludes it.

For example, if you use startAt(A) in a query, it returns the entire alphabet. If you use startAfter(A) instead, it returns B-Z.

// Get all cities with a population >= 1,000,000, ordered by population,
Firestore.collection("cities").orderBy("population").startAt(1000000);

Similarly, use the endAt() or endBefore() methods to define an end point for your query results.

// Get all cities with a population <= 1,000,000, ordered by population,
Firestore.collection("cities").orderBy("population").endAt(1000000);

Use a document snapshot to define the query cursor

TODO: this feature is not yet implemented into the ANE. We're working on it. :)