@hjdivad Just one question. I can't see an easy way of finding out the previous value of the changed properties using `didChange` and `willChange` doesn't seems to work.

Its not really indispensable to pass the previous values of the changed properties to the `invalidate` hook, but I think it would be a nice-to-have.

Should I care about it of do you think that is responsability of the user to previously store that information in the `instanceMeta`? In case you agree that it would be handy to pass the previous values of the properties that have just changed, how would you accomplish that?

I am learning a lot about ember internals this week :)