once method
Listens for exactly one event of the specified event type, and then stops listening.
Defaults to DatabaseEventType.value if no eventType
provided.
Implementation
Future<DatabaseEvent> once([
DatabaseEventType eventType = DatabaseEventType.value,
]) async {
switch (eventType) {
case DatabaseEventType.childAdded:
return DatabaseEvent._(
await _queryDelegate.onChildAdded(_modifiers).first,
);
case DatabaseEventType.childRemoved:
return DatabaseEvent._(
await _queryDelegate.onChildRemoved(_modifiers).first,
);
case DatabaseEventType.childChanged:
return DatabaseEvent._(
await _queryDelegate.onChildChanged(_modifiers).first,
);
case DatabaseEventType.childMoved:
return DatabaseEvent._(
await _queryDelegate.onChildMoved(_modifiers).first,
);
case DatabaseEventType.value:
return DatabaseEvent._(await _queryDelegate.onValue(_modifiers).first);
}
}