scrollTo works improperly

Which OS ?

Windows 10 x64

Version

Which versions I am using:

• react-native-swiper v 1.6.0-rc.3?
• react-native v0.63.2

Expected behaviour

When using inside onIndexChanged() it lags behind by 1 slide.

const MyScreen= () => {
const [currentIndex, setCurrentIndex] = useState(0);
const swiper = React.createRef();
const onIndexChanged = (index) => {
    console.log('Changed to ' + index);
    console.log(swiper.current.state.index);
    if (index > currentIndex) {
      console.log('Inside');
      swiper.current.scrollTo(currentIndex);
    }
  };
return (
    <Swiper
      ref={swiper}
      onIndexChanged={onIndexChanged}
      paginationStyle={styles.swiperPagination}
      dotColor={appColors.primary.dark}
      activeDotColor={appColors.primary.light}
      buttonWrapperStyle={{borderColor: 'white'}}
      loop={false}
      showsButtons
      nextButton={<Text style={styles.swiperButton}>›</Text>}
      prevButton={<Text style={styles.swiperButton}>‹</Text>}>
      {slides}
    </Swiper>

If I swipe left index changes to 1 (initial index = 0) and condition (index > currentIndex = true) is met, so it should be scrolled to slide with index 0

Actual behaviour

After left swipe condition (index > currentIndex = true) is met, so console logs 'Inside', but swiper.current.scrollTo(currentIndex) doesn't work. It happens because swiper state index value is one unit behind real index value and scrollTo function checks whether is it on the same slide, state says yes and nothing changes.

START!

SWIPE!


SWIPE!

So instead of immediate scrolling scrollTo function waits untill its state changes, and then it scrolls to slide with 0 index. As I have already mentioned it happens because swiper state index value is one unit behind real index value

How to reproduce it>

To help us, please fork this component, modify one example in examples folder to reproduce your issue and include link here.

• Link

Steps to reproduce

1. Create Swiper
2. Add onIndexChanged and ref props
3. Try to call scrollTo function inside of onIndexChanged function

Start with the reproduction in examples/components/Basic/index.js and trace the ref-based scrollTo call from onIndexChanged. Reproduce the one-slide lag described in the issue, then verify that scrollTo acts immediately on the requested index rather than waiting for the swiper state to update.