fixes async setState calls with ssr

[anilanar]

• Correctly checks whether component has already loaded or not in componentWillMount.

With SSR, componentWillMount was registering some setTimeout callbacks, calling setState asynchronously etc. This PR fixes it.

As far as I can see, res.resolved is never assigned to any value so it's always falsy. When componentWillMount is trigged; if loading is false, there's no point in doing the rest of the stuff. Because either loaded or error must be defined, so one of them can be rendered.

BTW, I have a suggestion for another PR: loading is a computable value: loading === !loaded && !error. So it makes sense to turn it into a computed value to reduce possible mistakes later on.

[carinakoo]

Would be great to see this merged to eliminate this warning on server rendering. 🙏

Warning: setState(...): Can only update a mounting component. This usually means you called setState() outside componentWillMount() on the server. This is a no-op. Please check the code for the LoadableComponent component.

[kettanaito]

Are you planning to merge this change?

It eliminates the error mentioned above gracefully.

[iamstarkov]

@tajo @thejameskyle can you release a new version with this patch?