emberjs/ember.js — pull request #5150 by mmpestorich (2014-07-11 22:37:11+00:00)
Title: [BUGFIX beta] Ember.computed.sort Observers

This commit ensures that observers are only added once to the sortPropertyDefinitions as they change.

Currently whenever the sortPropertyDefinitions change duplicate observers are being added for 'sortPropertyDefinitions.@each:change'. This eventually causes performance issues if the sortPropertyDefinitions change frequently as illustrated here: http://jsbin.com/tutoni/2/edit