blob: 964dc97b4d5787b5ad55ef1b36e36be0837ed5b4 [file] [log] [blame]
/// A class that helps implement equality
/// without needing to explicitly override == and [hashCode].
/// Equatables override their own == and [hashCode] based on
/// the provided `properties`.
abstract class Equatable {
/// The [List] of `props` (properties) which will be used to determine whether
/// two [Equatables] are equal.
final List 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([this.props = const []]);
@override
bool operator ==(Object other) =>
identical(this, other) ||
other is Equatable &&
runtimeType == other.runtimeType &&
_propsAreEqual(props, other.props);
@override
int get hashCode => runtimeType.hashCode ^ _propsHashCode;
int get _propsHashCode {
int hashCode = 0;
props.forEach((prop) {
hashCode = hashCode ^ prop.hashCode;
});
return hashCode;
}
bool _propsAreEqual(List props, List other) {
if (props.length != other.length) {
return false;
}
for (int i = 0; i < props.length; i++) {
if (props.elementAt(i) != other.elementAt(i)) {
return false;
}
}
return true;
}
}