Passing property name in property observer effect to the observing method

[aahoo]

Changing this line to

      fn.call(this, value, old, effect.property);

will make property observers way more useful. They can virtually replace the complex observer effect. In addition, the function being called knows what has changed from what to what to take the needed action.

[kaste]

Ideally we would just get the whole event information. See #3554 where I propose to also get the fromAbove value. Likewise #3573 where I propose custom effects which get both the path (property) you want and the fromAbove flag.

[TimvdLippe]

In general simple observers do not need this information, as they should be unique. If you do want to have 1 observer for all your properties, you can implement that yourself with a solution like http://jsbin.com/jiyawurudo/edit?html,console,output In general, the advice is to not duplicate this behavior and instead use a complex observer for these purposes.