beforeObserver (propertyNames, func) deprecatedprivate
Defined in packages/ember-metal/lib/mixin.js:794
When observers fire, they are called with the arguments obj, keyName. Note, @each.property observer is called per each add or replace of an element and it's not called with a specific enumeration item. A _beforeObserver fires before a property changes. A _beforeObserver is an alternative form of .observesBefore(). App.PersonView = Ember.View.extend({
friends: [{ name: 'Tom' }, { name: '