Interesting observation on difference between `array.filterBy` and `Ember.Computed.filterBy`

aprray-filter-vs-computed-filter.md

Apparently array.filterBy creates a new array based on the filtered content, whether Ember.Computed.filterBy reuses the same array.

This difference can be very important when you display a filtered list with {{each}} helper.

For eaxample, if you define the propery like this:

  filteredArray: function(){
    return this.get('content').filterBy('isDone', false);
  }.property('content.@each.isDone')

The whole {{each}} block will be rerendered every time the isDone flag of any record is changed.

If you use Ember.computed instead, the only changed records will be rerendered:

  filteredComputed: Ember.computed.filterBy('content','isDone', false)

Here is a quick example : http://jsbin.com/uHOvANoJ/7/edit?html,js,console,output