Add Animated.useCode hook as an alternative to Animated.Code

[jeremy-deutsch]

I'm not sure about the current stance on adding hooks to react-native-reanimated, but this adds an Animated.useCode hook with an API halfway between useEffect and Animated.Code, that serves as an alternative to Animated.Code. Instead of passing in a callback, the user passes in a reanimated node to execute, along with an array of dependencies. Since we use useEffect under the hood, any change in the dependency array also causes the node to be updated.

One piece of behavior that I'm still iffy on is what happens if a dependency array isn't passed in. The idea is that one is always passed in (the typings reflect this), but right now, not passing one in causes the node to be re-run on every render. I think this is expected enough that we can leave it as is.

Also, this is kind of obvious, but Animated.useCode is a no-op on a version of RN without hooks.

[osdnk]

Super cool
Just add docs and ts :)

[jeremy-deutsch]

Thanks! TS is in there - I'll put up some docs soon

[jeremy-deutsch]

Docs added! Pretty short, but I think the Animated.Code description and the example get the point across.

[osdnk]

Nice, like it! 😄

[osdnk]

May I ask for one more thing? Could you add an example in an app showing how to use it, @jeremy-deutsch?

[osdnk]

But I'm going to merge it now 😄