Thank you everyone for your enthusiasm and positive overall feedback on the Animation In and Out RFC. Given the positive response, we're going to move forward with the proposed design. It's exciting to see a very animated set of responses.

RFC Questions

Q1: Should these options support setting styles directly like ngStyle bindings?
The feedback was clear that ngStyle-like bindings are not needed for animations, and that classes are preferred.

Q2: Is animate.in strictly necessary given the platform supports this behavior already?
There were a few mixed opinions here, but the large majority prefer that we keep animate.in for symmetry, the benefit of the class removal, and function support.

Q3: What is your preference on the naming? animate.in and animate.out? animate.enter and animate.leave? Something else?
Opinions here were very mixed with roughly a third of commenters preferring enter and leave rather than in and out. We will take this into consideration as we decide which to use.

Q4: Which of these 2 options (callback function vs ExtendableEvent + promise) for using functions is the most ideal to you, and why? Do you have an alternative suggestion?
The vast majority of people preferred the simplicity of the callback function. There were a couple of responses that preferred the event + promise syntax.

Q5: What would you want out of testing tools for animations?
This was the weakest of the feedback. Some people would like the ability to tick forward the animation. Some just want to be able to know if the classes have been added. For many, being able to disable animations in tests is the most important thing.

Thank you for your feedback! Watch the Angular repository for updates on when the new animations code will be added.