[Docs] Add setNativeProps documentation (Original title: clear() function on TextInput)

[d-vine]

The problem: I need to clear a TextInput after some user interaction.

The request: expose some kind of clear() or even setText() functionality.

I understand that this is exactly the mutative approach to UI programming, that React is trying to get rid of. But as the docs state them selfs, a controlled approach to the TextInput component using the value property doesn't perform.
My current solution is to set the value property to null once on the next render after the user interaction. But this feels rather clunky. Since the declarative approach seems to break down with the TextInput implementation I would argue for exposing the mutative API.

[brentvatne]

@dvine-multimedia - are you using setNativeProps to set the value to null?

setNativeProps example
controlled setState example

[d-vine]

@brentvatne I didn't realize that setNativeProps actually is the mutation API I was looking for. Thanks a lot. Maybe there could be some more documentation on that? But I don't know if react really want's to encourrage the usage of setNativePropsexcept for a few special cases.

[brentvatne]

@dvine-multimedia - good point, documentation for setNativeProps would be useful! Related - it might also be useful to add documentation for the issues faced in this discussion - also pertaining to communicating directly from js->native

[grabbou]

Haven't seen any notes about blur and other methods available on a given component, is this something we would be interested in describing as well?

[ide]

@grabbou yes, would be good to document public methods like blur().

[brentvatne]

@grabbou - any interest in adding some documentation for blur() and focus()?

[grabbou]

Yeah, can add in some descriptions, any hints what's the appropriate place for them speaking docs structure wise?

[brentvatne]

@grabbou - TextInput seems like the best spot

[brentvatne]

@grabbou - I'm going to close this issue, can you open a PR for that when it's ready? Thanks 😄

[brentvatne]

Docs that cover setNativeProps for TextInput clearing are here: https://facebook.github.io/react-native/docs/direct-manipulation.html#setnativeprops-to-clear-textinput-value

[grabbou]

Ah, nice! Will send over later today.