endAt method
Create a query constrained to only return child nodes with a value less than or equal to the given value, using the given orderBy directive or priority as default, and optionally only child nodes with a key less than or equal to the given key.
Implementation
Query endAt(dynamic value, {String key}) {
assert(!_parameters.containsKey('endAt'));
assert(value is String ||
value is bool ||
value is double ||
value is int ||
value == null);
final Map<String, dynamic> parameters = <String, dynamic>{'endAt': value};
if (key != null) parameters['endAtKey'] = key;
return _copyWithParameters(parameters);
}