orderByFieldPath method

Query<T> orderByFieldPath(FieldPath fieldPath, { bool descending = false, })

Creates and returns a new Query that's additionally sorted by the specified field, optionally in descending order instead of ascending.

This function returns a new (immutable) instance of the Query (rather than modify the existing instance) to impose the field mask.

• fieldPath: The field to sort by.
• descending (false by default) Whether to obtain documents in descending order.

final query = firestore.collection('col').where('foo', WhereFilter.equal, 42);

query.orderBy('foo', descending: true).get().then((querySnapshot) {
  querySnapshot.forEach((documentSnapshot) {
    print('Found document at ${documentSnapshot.ref.path}');
  });
});

Implementation

Query<T> orderByFieldPath(
  FieldPath fieldPath, {
  bool descending = false,
}) {
  if (_queryOptions.startAt != null || _queryOptions.endAt != null) {
    throw ArgumentError(
      'Cannot specify an orderBy() constraint after calling '
      'startAt(), startAfter(), endBefore() or endAt().',
    );
  }

  final newOrder = _FieldOrder(
    fieldPath: fieldPath,
    direction: descending ? _Direction.descending : _Direction.ascending,
  );

  final options = _queryOptions.copyWith(
    fieldOrders: [..._queryOptions.fieldOrders, newOrder],
  );
  return Query<T>._(
    firestore: firestore,
    queryOptions: options,
  );
}