js/libs/ember-1.5.1.js
function(idx, object) {
    if (idx > get(this, 'length')) throw new Ember.Error(OUT_OF_RANGE_EXCEPTION) ;
    this.replace(idx, 0, [object]) ;
    return this ;
  }
function(idx, object) {
    if (idx > get(this, 'length')) throw new Ember.Error(OUT_OF_RANGE_EXCEPTION) ;
    this.replace(idx, 0, [object]) ;
    return this ;
  }
This will use the primitive `replace()` method to insert an object at the
specified index.

```javascript
var colors = ["red", "green", "blue"];
colors.insertAt(2, "yellow");  // ["red", "green", "yellow", "blue"]
colors.insertAt(5, "orange");  // Error: Index out of range
```

@method insertAt
@param {Number} idx index of insert the object at.
@param {Object} object object to insert
@return this