Pass State Types to Swiper Component

[liamfd]

Is it a bugfix ?

• Yes or No ? No
• If yes, which issue (fix #number) ? I didn't see an open issue for this

Is it a new feature ?

• Yes or no ? No (I don't think so)
• Include documentation, demo GIF if applicable

Describe what you've done:

In trying to do something along the lines of:

  const swiper = React.useRef<ReactNativeSwiper>(null);
  
  React.useEffect(() => {
      if (!swiper.current) {
        return;
      }
      if (swiper.current.state.index !== indexOfNextQuestion) {
        swiper.current.scrollBy(
          indexOfNextQuestion - swiper.current.state.index,
          true
        );
  }

TypeScript was saying "Property 'index' does not exist on type 'Readonly<{}>'." on swiper.current.state.index, even though the value was defined at runtime and these values appeared to be defined in state in the component's source code.

In looking at the types, it looked like the state wasn't being passed to the React.Component type, so it made sense that TS believed that the state object was empty. Applying this change resolves that.

How to test it ?

I've tested it in my project. I imagine anything that tries to pull state off of a ref will encounter this issue. Happy to try to put together a quick test project if that would be useful.

Thank you for your work on this project, please let me know if I there's anything I can do to improve this PR!

[ArrayZoneYour]

@liamfd Good job👍
Can you rename SwiperStates to SwiperState by the way? I think xxxState is better.

[liamfd]

@ArrayZoneYour thanks! Renamed it to SwiperState, I like that naming too.