What is the relationship? Is there a common type knowable at compile-time between these?
Situation: The emit() function used by BLoC when transforming its State on Events does a comparison using ==.
Q1. Are instances of the same empty definition subtype that are neither Immutable, Canonical, Equatable to be considered equal?
No. You only get == comparison between instances for free when (1) a constant constructor is defined for the class and (2) both objects are instantiated as constants.
class Model {
const Model();
}
final m = const Model();That is canonicalized, which must be immutable.
Q2. I want to know the simplest approach of the 3 methods to take consistently in order to guarantee this works correctly.
If you want mutable or complex aggregate object state then simply implementing Equatable's props => []; method is very easy.
Otherwise Canonicalized object is less prone to errors and bugs.
What is the relationship? Is there a common type knowable at compile-time between these?
Situation: The
emit()function used by BLoC when transforming its State on Events does a comparison using==.Q1. Are instances of the same empty definition subtype that are neither Immutable, Canonical, Equatable to be considered equal?
No. You only get
==comparison between instances for free when (1) a constant constructor is defined for the class and (2) both objects are instantiated as constants.That is canonicalized, which must be immutable.
Q2. I want to know the simplest approach of the 3 methods to take consistently in order to guarantee this works correctly.
If you want mutable or complex aggregate object state then simply implementing Equatable's
props => [];method is very easy.Otherwise Canonicalized object is less prone to errors and bugs.