js/libs/ember-1.5.1.js
function() {
    if (this.isFrozen) { throw new Ember.Error(Ember.FROZEN_ERROR); }

    var len = get(this, 'length');
    if (len === 0) { return this; }

    var guid;

    this.enumerableContentWillChange(len, 0);
    Ember.propertyWillChange(this, 'firstObject');
    Ember.propertyWillChange(this, 'lastObject');

    for (var i=0; i < len; i++) {
      guid = guidFor(this[i]);
      delete this[guid];
      delete this[i];
    }

    set(this, 'length', 0);

    Ember.propertyDidChange(this, 'firstObject');
    Ember.propertyDidChange(this, 'lastObject');
    this.enumerableContentDidChange(len, 0);

    return this;
  }
function() {
    if (this.isFrozen) { throw new Ember.Error(Ember.FROZEN_ERROR); }

    var len = get(this, 'length');
    if (len === 0) { return this; }

    var guid;

    this.enumerableContentWillChange(len, 0);
    Ember.propertyWillChange(this, 'firstObject');
    Ember.propertyWillChange(this, 'lastObject');

    for (var i=0; i < len; i++) {
      guid = guidFor(this[i]);
      delete this[guid];
      delete this[i];
    }

    set(this, 'length', 0);

    Ember.propertyDidChange(this, 'firstObject');
    Ember.propertyDidChange(this, 'lastObject');
    this.enumerableContentDidChange(len, 0);

    return this;
  }
Clears the set. This is useful if you want to reuse an existing set
without having to recreate it.

```javascript
var colors = new Ember.Set(["red", "green", "blue"]);
colors.length;  // 3
colors.clear();
colors.length;  // 0
```

@method clear
@return {Ember.Set} An empty Set