handleHorizontalScroll()

in js/common/ViewPager.js [147:175]

• 26 lines of code
• 8 McCabe index (conditional complexity)

  handleHorizontalScroll(e: any) {
    let selectedIndex = e.nativeEvent.position;
    if (selectedIndex === undefined) {
      selectedIndex = Math.round(
        e.nativeEvent.contentOffset.x / this.state.width
      );
    }
    if (selectedIndex < 0 || selectedIndex >= this.props.count) {
      return;
    }
    if (
      this.state.scrollingTo !== null &&
      this.state.scrollingTo !== selectedIndex
    ) {
      return;
    }
    if (
      this.props.selectedIndex !== selectedIndex ||
      this.state.scrollingTo !== null
    ) {
      this.setState({ selectedIndex, scrollingTo: null }, () => {
        // the onSelectedIndexChange handler can change props.selectedIndex, so we want
        // to call it after the state has actually changed to avoid extra scrollTo call
        // (see componentWillReceiveProps)
        const { onSelectedIndexChange } = this.props;
        onSelectedIndexChange && onSelectedIndexChange(selectedIndex);
      });
    }
  }