| /// A class that helps implement determine equality |
| /// without needing to explicitly override == and [hashCode]. |
| /// Equatables override their own == and [hashCode] based on |
| /// the provided `properties`. |
| abstract class Equatable { |
| /// The [Set] of `props` (properties) which will be used to determine whether |
| /// two [Equatables] are equal. |
| final Set props; |
| |
| /// The constructor takes an optional [Iterable] of `props` which |
| /// will be used to determine whether two [Equatables] are equal. |
| /// If no properties are provided, `props` will be initialized to |
| /// `Iterable.empty()`. |
| Equatable([Iterable props]) |
| : this.props = Set.from(props ?? Iterable.empty()); |
| |
| @override |
| bool operator ==(Object other) => |
| identical(this, other) || |
| other is Equatable && |
| runtimeType == other.runtimeType && |
| this.props.containsAll(other.props); |
| |
| @override |
| int get hashCode => _hashCode(); |
| |
| int _hashCode() { |
| int hashCode = runtimeType.hashCode; |
| |
| props.forEach((prop) { |
| hashCode = hashCode ^ prop.hashCode; |
| }); |
| |
| return hashCode; |
| } |
| } |