react-native-reanimated/lib/reanimated2/hook/useAnimatedScrollHandler.js

More powerful alternative to Animated library for React Native.

import { useEvent, useHandler } from './Hooks';
export function useAnimatedScrollHandler(handlers, dependencies) {
    // case when handlers is a function
    const scrollHandlers = typeof handlers === 'function' ? { onScroll: handlers } : handlers;
    const { context, doDependenciesDiffer } = useHandler(scrollHandlers, dependencies);
    // build event subscription array
    const subscribeForEvents = ['onScroll'];
    if (scrollHandlers.onBeginDrag !== undefined) {
        subscribeForEvents.push('onScrollBeginDrag');
    }
    if (scrollHandlers.onEndDrag !== undefined) {
        subscribeForEvents.push('onScrollEndDrag');
    }
    if (scrollHandlers.onMomentumBegin !== undefined) {
        subscribeForEvents.push('onMomentumScrollBegin');
    }
    if (scrollHandlers.onMomentumEnd !== undefined) {
        subscribeForEvents.push('onMomentumScrollEnd');
    }
    return useEvent((event) => {
        'worklet';
        const { onScroll, onBeginDrag, onEndDrag, onMomentumBegin, onMomentumEnd, } = scrollHandlers;
        if (onScroll && event.eventName.endsWith('onScroll')) {
            onScroll(event, context);
        }
        else if (onBeginDrag && event.eventName.endsWith('onScrollBeginDrag')) {
            onBeginDrag(event, context);
        }
        else if (onEndDrag && event.eventName.endsWith('onScrollEndDrag')) {
            onEndDrag(event, context);
        }
        else if (onMomentumBegin &&
            event.eventName.endsWith('onMomentumScrollBegin')) {
            onMomentumBegin(event, context);
        }
        else if (onMomentumEnd &&
            event.eventName.endsWith('onMomentumScrollEnd')) {
            onMomentumEnd(event, context);
        }
    }, subscribeForEvents, doDependenciesDiffer);
}