Temporarily revert "Add exact type checker from react native"

[gaearon]

Reverts #41

cc @aweary

There were two issues that were missed during review:

Prod version

See this comment. Lists in these two files must be in sync. This is essential because as far as I can see PropTypes.exact({}).isRequired will throw in production code.

We need to automate this check because I agree it's not obvious.

Object.assign

I don't think this repo is set up to polyfill Object.assign yet, so this will throw in older browsers.

Way forward

@aweary Can you fix those two issues? Happy to take the PR back in after that.

For now I have to revert because I don't have time to fix forward and I'm worried we'll forget about this, and ship a broken version.

[ljharb]

object.assign is a great non-auto-shimming polyfill if you need one :-)

[gaearon]

We're using object-assign in React repo so would make sense for consistency.
We should really set up Babel here to match our transforms..

[ljharb]

(you should use object.assign there too :-p)

Regardless of which module you use, you should use https://www.npmjs.com/package/babel-plugin-transform-replace-object-assign so that babel correctly transpiles object spread and Object.assign to use the module.

[aweary]

@gaearon sorry about that, I wasn't aware of either of those conditions ☹️ I can fix, but not until next week unfortunately.