Class Map
TopLevel
Class Map
Object
Map
Map objects are collections of key/value pairs where both the keys and values may be arbitrary ECMAScript language values. A distinct key value may only occur in one key/value pair within the Map's collection. Key/value pairs are stored and iterated in insertion order.
API Versioned:
From version 21.2.
Properties
size  :  Number
Number of key/value pairs stored in this map.
Constructor Summary
Map()
Creates an empty map.
Map(values : Iterable)
If the passed value is null or undefined then an empty map is constructed.
Method Summary
clear() : void
Removes all key/value pairs from this map.
delete(key : Object) : boolean
Removes the entry for the given key.
entries() : ES6Iterator
Returns an iterator containing all key/value pairs of this map.
forEach(callback : Function) : void
Runs the provided callback function once for each key/value pair present in this map.
forEach(callback : Function, thisObject : Object) : void
Runs the provided callback function once for each key/value pair present in this map.
get(key : Object) : Object
Returns the value associated with the given key.
has(key : Object) : boolean
Returns if this map has value associated with the given key.
keys() : ES6Iterator
Returns an iterator containing all keys of this map.
set(key : Object, value : Object) : Map
Adds or updates a key/value pair to the map.
values() : ES6Iterator
Returns an iterator containing all values of this map.
Constructor Detail
Map
public Map()
Creates an empty map.

Map
public Map(values : Iterable)
If the passed value is null or undefined then an empty map is constructed. Else an iterator object is expected that produces a two element array-like object whose first element is a value that will be used as a Map key and whose second element is the value to associate with that key.
Parameters:
values - The initial map values

Method Detail
clear
clear() : void
Removes all key/value pairs from this map.

delete
delete(key : Object) : boolean
Removes the entry for the given key.
Parameters:
key - The key of the key/value pair to be removed from the map.
Returns:
true if the map contained an entry for the passed key that was removed. Else false is returned.

entries
entries() : ES6Iterator
Returns an iterator containing all key/value pairs of this map. The iterator produces a series of two-element arrays with the first element as the key and the second element as the value.

forEach
forEach(callback : Function) : void
Runs the provided callback function once for each key/value pair present in this map.
Parameters:
callback - The function to call, which is invoked with three arguments: the value of the element, the key of the element, and the Map object being iterated.

forEach
forEach(callback : Function, thisObject : Object) : void
Runs the provided callback function once for each key/value pair present in this map.
Parameters:
callback - The function to call, which is invoked with three arguments: the value of the element, the key of the element, and the Map object being iterated.
thisObject - The Object to use as 'this' when executing callback.

get
get(key : Object) : Object
Returns the value associated with the given key.
Parameters:
key - The key to look for.
Returns:
The value associated with the given key if an entry with the key exists else undefined is returned.

has
has(key : Object) : boolean
Returns if this map has value associated with the given key.
Parameters:
key - The key to look for.
Returns:
true if an entry with the key exists else false is returned.

keys
keys() : ES6Iterator
Returns an iterator containing all keys of this map.

set
set(key : Object, value : Object) : Map
Adds or updates a key/value pair to the map.
You can't use JavaScript bracket notation to access map entries. JavaScript bracket notation accesses only properties for Map objects, not map entries.
Parameters:
key - The key object.
value - The value to be associated with the key.
Returns:
This map object.

values
values() : ES6Iterator
Returns an iterator containing all values of this map.