propertyWillChange (keyName) Ember.Observable
private
Notify the observer system that a property is about to change.
Sometimes you need to change a value directly or indirectly without actually calling get()
or set()
on it. In this case, you can use this method and propertyDidChange()
instead. Calling these two methods together will notify all observers that the property has potentially changed value.
Note that you must always call propertyWillChange
and propertyDidChange
as a pair. If you do not, it may get the property change groups out of order and cause notifications to be delivered more often than you would like.
Parameters:
-
keyName
String
- The property key that is about to change.
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