equality method
Implementation
bool equality(value, itemValue) {
try {
if (comparingBy == null) {
if (multiple) {
return values!.contains(itemValue);
}
return value == itemValue;
}
if (multiple) {
return values!.any(comparingBy!(itemValue));
}
return comparingBy!(value) == comparingBy!(itemValue);
} catch (e) {
return false;
}
}