dart:collection
 MapBase<K, V> class 
  Base class for implementing a Map.
 This class has a basic implementation of all but five of the members of Map. A basic Map class can be implemented by extending this class and implementing keys, operator[], operator[]=, remove and clear. The remaining operations are implemented in terms of these five.
 The keys iterable should have efficient Iterable.length and Iterable.contains operations, and it should catch concurrent modifications of the keys while iterating.
 A more efficient implementation is usually possible by overriding some of the other members as well.
    - Inheritance
   - Implementers
   
   Constructors
  -  MapBase() 
   
   Properties
  -  entries → Iterable<MapEntry<K, V>> 
read-only, inherited
  -  The map entries of this.  
  -  hashCode → int 
read-only, inherited
  -  The hash code for this object. [...]  
  -  isEmpty → bool 
read-only, inherited
  -  Returns true if there is no key/value pair in the map.  
  -  isNotEmpty → bool 
read-only, inherited
  -  Returns true if there is at least one key/value pair in the map.  
  -  keys → Iterable<K> 
read-only, inherited
  -  The keys of this. [...]  
  -  length → int 
read-only, inherited
  -  The number of key/value pairs in the map.  
  -  runtimeType → Type 
read-only, inherited
  -  A representation of the runtime type of the object.  
  -  values → Iterable<V> 
read-only, inherited
  -  The values of this. [...]  
  
   Methods
  -  addAll(Map<K, V> other) → void  
inherited
  -  Adds all key/value pairs of 
other to this map. [...]    -  addEntries(Iterable<MapEntry<K, V>> newEntries) → void  
inherited
  -  Adds all key/value pairs of 
newEntries to this map. [...]    -  cast<RK, RV>() → Map<RK, RV>  
inherited
  -  Provides a view of this map as having 
RK keys and RV instances, if necessary. [...]    -  clear() → void  
inherited
  -  Removes all pairs from the map. [...]  
  -  containsKey(Object key) → bool  
inherited
  -  Returns true if this map contains the given 
key. [...]    -  containsValue(Object value) → bool  
inherited
  -  Returns true if this map contains the given 
value. [...]    -  forEach(void action(K key,  V value)) → void  
inherited
  -  Applies 
f to each key/value pair of the map. [...]    -  map<K2, V2>(MapEntry<K2, V2> transform(K key,  V value)) → Map<K2, V2>  
inherited
  -  Returns a new map where all entries of this map are transformed by the given 
f function.    -  noSuchMethod(Invocation invocation) → dynamic  
inherited
  -  Invoked when a non-existent method or property is accessed. [...]  
  -  putIfAbsent(K key,  V ifAbsent()) → V  
inherited
  -  Look up the value of 
key, or add a new value if it isn't there. [...]    -  remove(Object key) → V  
inherited
  -  Removes 
key and its associated value, if present, from the map. [...]    -  removeWhere(bool test(K key,  V value)) → void  
inherited
  -  Removes all entries of this map that satisfy the given 
predicate.    -  toString() → String  
inherited
  -  Returns a string representation of this object.  
  -  update(K key,  V update(V value), { V ifAbsent() }) → V  
inherited
  -  Updates the value for the provided 
key. [...]    -  updateAll(V update(K key,  V value)) → void  
inherited
  -  Updates all values. [...]  
  
   Operators
  -  operator ==(dynamic other) → bool  
inherited
  -  The equality operator. [...]  
  -  operator [](Object key) → V  
inherited
  -  Returns the value for the given 
key or null if key is not in the map. [...]    -  operator []=(K key,  V value) → void  
inherited
  -  Associates the 
key with the given value. [...]    
   Static Methods
  -  mapToString(Map m) → String