You might want to consider adding a way to get the TweenMax instance that’s currently active inside your proxy so that folks can call pause(), resume(), reverse(), get the progress of the tween, etc.

Actually, I seriously considered adding a proxy to the core TweenMax class a little while ago, and actually built it out and it was working great (with any property), but then I realized that a setDestination() method would actually allow more flexibility because it can accept parameters. Normally, if you just update the destination values and the starting values stay the same, then you’ll see a sudden jump if the tween is in progress. However, TweenMax’s new setDestination() allows you to decide if you want that behavior or if you want TweenMax to adjust the start values so that the tween appears seamless (no sudden jump).

I believe Grant’s implementation causes the tween to start over again every time you change the property. So if you have a 3-second tween, and then 2.5 seconds into it, you change the destination value, it’ll tween for another 3 seconds and the easing will start over again as well. That’s not necessarily bad at all – just something to keep in mind. TweenMax’s setDestination() honors both the duration and the easing.

I released a big update to TweenMax today that adds a bunch of features including the setDestination() method. http://www.TweenMax.com

Thanks again for sharing, Jonathan!