have setState work with key, value along with an object

[piranha]

This fixes #175 if you're willing to accept it. I'm not sure if that's the best way to document it and I'll gladly make any fixes you want to get it in. :)

This change makes it easier to work with React's API when key is generated programmatically.

[chenglou]

The argument for this is that this fits well into the way lots of other libraries work (e.g. backbone), and frankly I did make the mistake several time at the beginning of using the above format. the argument (more or less) against this is that we could simply put a check and a warning message.

[zpao]

I think you saw some of our discussions on IRC about this. I think this is totally reasonable to do, we think we might just want to come up with a more explicit API. cc @jordwalke @sebmarkbage

[piranha]

Thank you for reminding me about this pull request, I remembered that I promised to write tests for it and got distracted. :-) I'm not sure about API, but this looks like Backbone's Model.set function right now.

[sebmarkbage]

I think the reason we didn't have this is to avoid problems with key mangling. E.g. in closure compiler.

Previously we didn't have batching of setState commands which also meant that you wanted to pack as many props as possible into a single setState.

I think this a reasonable want for dynamic keys. I'm curious about the usage of dynamic keys though. How are you using this right now? Would it make more sense to use something like a Map abstraction that prevents problems with proto keys and all the other problems using objects as maps?

setState({ myMap: new Map() });

... later

this.state.myMap.set(key, value);
this.forceUpdate();

[piranha]

I use it in FormMixin:

exports.FormMixin =
    inputChange: (e) ->
        obj = {}
        obj[e.target.name] = e.target.value
        @setState(obj)

Just thought that in Backbone that was easier. But you are right, that would break compatibility with closure compiler; even in my case it would be better to have a mapping or something...

[piranha]

As I think about it more it's better not to have this. :-) linkState from new react removes my need, and I would love to see React working with Closure Compiler advanced mode.

[petehunt]

:) also see ReactStateSetters (another internal thing we should probably expose).