Removing transitions API

[tbranyen]

Transitions were a top level API that allowed developers to hook into and halt lifecycle changes in the DOM. For instance if you are closing a menu, you could halt the removeChild, and animate it away smoothly first. I have recently merged in a change that fully backs this API out of the project. I haven't released any new versions yet with this change, but I suspect this will be permanent.

I'm going to dig into all the current known usage of diffhtml which is ~200 projects and find out if this breaks any existing users.

Problems with this API:

• Requires async, without transitions the entire core is synchronous
• Needed to schedule transactions, vs just firing them off sequentially
• Weren't very easy to use, which meant creating custom middleware to be more user-friendly
• With all the additional code needed, we added ~2kb to the min+gzip build 5kb -> 7kb

Benefits of the API:

• Can animate pretty much anything, could create a frame-based animation tool similar to Flash
• Provided hooks into various DOM events that aren't easily possible with middleware

[tbranyen]

Tried to get more data from Twitter, but hard to get a signal. Might need to reach out to specific consumers directly to get some input.

[tbranyen]

https://github.com/search?q=diffhtml-middleware-inline-transitions&type=code

The TodoMVC app was the only usage of the middleware.

https://github.com/search?l=JavaScript&p=1&q=addTransitionState&type=Code
https://github.com/search?l=JavaScript&p=1&q=removeTransitionState&type=Code

There is no known usage of removeTransitionState or addTransitionState.

[tbranyen]

I think for now I'll keep removed, and if someone comes up with a need for it we can backreference the old source and bring in legacy compatibility. I'm only one person, so don't want to create unnecessary work for the sake of completeness.