fix state not correct sync

[zombieJ]

Current getDerivedStateFromProps get state ood when setState is called which is not same behavior as React 16.3

var state = this.constructor.getDerivedStateFromProps(nextProps, this.state);

Sample: https://codesandbox.io/s/nw3k9kqk00

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PS: But in old version of react, this change will cause re-render when user return null.

[bvaughn]

Ah, nice catch!

[bvaughn]

I added a test (45c32b7) that failed before this fix to guard against a regression.

[bvaughn]

Just published v3.0.3 with this fix. Thanks for the PR! 😄

[Hypnosphi]

This throws with react-test-renderer because it doesn't pass this to updater function https://github.com/facebook/react/blob/master/packages/react-test-renderer/src/ReactShallowRenderer.js#L301

The fix would be just to use arrow function, I'll submit a PR