====== Hash ======
Here is the [[http://docs.mootools.net/Native/Hash|documentation for Hash.js]].

The //Hash// returns a hash map object with various helper functions for managing a JavaScript object. We must use //.set//, //.get//, and //.remove// to add/change, retrieve and remove values; we must not access the internal object directly. null values are allowed. Pass in an object to convert to a Hash.

<code javascript>
var hash = new Hash({a: 'hi', b: 'world', c: 'howdy'});
</code>

===== Hash.set, .get, .remove =====
These functions must be used to interact with the data in a //Hash//.
<code javascript exec>
var hash = new Hash({a: 'hi', b: 'world', c: 'howdy'});
hash.set('a', 'blah');
hash.remove('b');
console.log(hash.get('a')); /*blah*/
console.log(hash.get('b')); /*undefined*/
</code>

===== Hash.has =====
Check for a key in the map.
<code javascript exec>
var hash = new Hash({a: 'hi', b: 'world', c: 'howdy'});
console.log(hash.has('c')); /* true */
console.log(hash.has('d')); /* false */
</code>

===== Hash.hasValue =====
Checks for a value in the map.

<code javascript exec>
var hash = new Hash({a: 'hi', b: 'world', c: 'howdy'});
console.log(hash.hasValue('hi')); /* true */
console.log(hash.hasValue('Guttentag!')); /* false */
</code>

===== Hash.each =====
Iterate over the //Hash// and execute a function for the value of each property. Takes as an optional second argument (the first is the function) a bind object.
<code javascript exec>
var hash = new Hash({a: 'hi', b: 'world', c: 'howdy'});
/*alert 'hi', 'world', and 'howdy'*/
hash.each(function(val){
	alert(val);
});
</code>

===== Hash.keyOf =====
//Hash.keyOf// returns the key for a specified value:

<code javascript exec>
var hash = new Hash({a: 'hi', b: 'world', c: 'howdy'});
hash.keyOf('howdy'); //c
</code>

===== Hash.extend, Hash.combine =====
Add the key values of the passed in object to the hash map. **Duplicate values are overwritten.**
<code javascript exec>
var hash = new Hash({a: 'hi', b: 'world', c: 'howdy'});
hash.extend({c:'blah', d:'something'});
/*hash now has a, b, c, and d*/
console.log(hash.get('c')); /* 'blah' */
console.log(hash.getKeys());
console.log(hash.getValues());
</code>

//Hash.combine// will do the same thing but you can pass in more than one item. Note that //combine// excludes duplicates, unlike //extend// which overwrites.

<code javascript exec>
var hash = new Hash({a: 'hi', b: 'world', c: 'howdy'});
hash.combine({c:'blah', d:'something', e: 'cakes', f: 'cookies'});
/*hash now has a, b, c, d, e, and f*/
console.log(hash.get('c')); /* 'howdy' */
console.log(hash.getKeys());
console.log(hash.getValues());
</code>


===== Hash.empty =====
**This has changed in MooTools 1.1** - now //Hash.empty// clears the contents of the //Hash// and returns itself. It used to return //true// (if the //Hash// was empty) or //false//.

<code javascript exec>
var hash = new Hash({a: 'hi', b: 'world', c: 'howdy'});
hash.empty();
console.log(hash.getKeys().length); //zero
</code>

===== Hash.getKeys, .getValues =====
Returns an array of the keys and values of the hash map.
<code javascript exec>
var hash = new Hash({a: 'hi', b: 'world', c: 'howdy'});
console.log(hash.getKeys()); /*	[a, b, c]	*/
console.log(hash.getValues()); /*	['hi', 'world', 'howdy']	*/
</code>

===== $H =====
Just a short hand for //new Hash();//

===== Deprecated Methods =====
The following methods are no longer available in MooTools 1.2:

   * Hash.length (use //Hash.getKeys().length//)
   * Hash.hasKey (use //Hash.has//)
   * Hash.keys (use //Hash.getKeys//)
   * Hash.values (use //Hash.getValues//)