Cloud Firestore Client - Class QuerySnapshot (1.38.0)

use Google\Cloud\Firestore\FirestoreClient;

$firestore = new FirestoreClient();
$collection = $firestore->collection('users');
$query = $collection->where('age', '>', 18);

$snapshot = $query->documents();

// Snapshots can be iterated with foreach:
foreach ($snapshot as $user) {
    echo $user['name'] . PHP_EOL;
}

$empty = $snapshot->isEmpty();

$size = $snapshot->size();

$rows = $snapshot->rows();