# MapChange<K, V> class

Represents a change in a `Map`.

This event captures information about changes to key-value pairs, including additions, updates, removals, and clear operations.

### Example

    void main() {
      var putEvent = MapChange.put('Alice', 10, 20);
      print(putEvent.type); // MapChangeType.put

      var removeEvent = MapChange.remove('Bob', 15);
      print(removeEvent.oldValue); // 15
    }

Inheritance
  - Object
  - ObsEvent
  - MapChange
Annotations
  - @Generic(MapChange)

## Constructors

MapChange.clear([K? key])
  Represents a change in a `Map`.
  const
MapChange.put(K? key, V? oldValue, V? newValue)
  Represents a change in a `Map`.
  const
MapChange.remove(K? key, V? oldValue)
  Represents a change in a `Map`.
  const

## Properties

hashCode → int
  The hash code for this object.
  no setter inherited
key → K?
  The key affected by the change (if applicable).
  final
newValue → V?
  The new value associated with the key (if applicable).
  final
oldValue → V?
  The previous value associated with the key (if applicable).
  final
runtimeType → Type
  A representation of the runtime type of the object.
  no setter inherited
type → MapChangeType
  The type of change that occurred in the map.
  final

## Methods

noSuchMethod(Invocation invocation) → dynamic
  Invoked when a nonexistent method or property is accessed.
  inherited
toString() → String
  A string representation of this object.
  inherited

## Operators

operator ==(Object other) → bool
  The equality operator.
  inherited