EqualityBy<E, F> class

Equality of objects based on derived values.

For example, given the class:

abstract class Employee {
  int get employmentId;
}

The following Equality considers employees with the same IDs to be equal:

EqualityBy((Employee e) => e.employmentId);

It's also possible to pass an additional equality instance that should be used to compare the value itself.

Implemented types

Constructors

EqualityBy(F comparisonKey(E), [Equality<F> inner = const DefaultEquality<Never>()])

hashCode → int: The hash code for this object.
no setterinherited
runtimeType → Type: A representation of the runtime type of the object.
no setterinherited

equals(E e1, E e2) → bool: Compare two elements for being equal.
override
hash(E e) → int: Creates a combined hash code for a number of objects.
override
isValidKey(Object? o) → bool: Test whether an object is a valid argument to equals and hash.
override
noSuchMethod(Invocation invocation) → dynamic: Invoked when a nonexistent method or property is accessed.
inherited
toString() → String: A string representation of this object.
inherited