@quidone/react-native-wheel-picker/dest/module/base/picker/hooks/useSyncScrollEffect.js

Picker is a UI component for selecting an item from a list of options.

"use strict";

import { useEffect, useRef } from 'react';
import { useStableCallback } from '@rozhkov/react-useful-hooks';
import { useEffectWithDynamicDepsLength } from '../../../utils/react';
const SYNC_SCROLL_DELAY_MS = 100;
const useSyncScrollEffect = ({
  listRef,
  value,
  valueIndex,
  extraValues = [],
  activeIndexRef,
  touching,
  enableSyncScrollAfterScrollEnd
}) => {
  const timeoutId = useRef(undefined);
  const isScrollingRef = useRef(false);
  const prevEnableSyncScrollAfterScrollEnd = useRef(enableSyncScrollAfterScrollEnd);
  const cancelSyncScroll = useStableCallback(() => {
    clearTimeout(timeoutId.current);
    timeoutId.current = undefined;
  });
  const syncScroll = useStableCallback(() => {
    if (listRef.current == null || touching || activeIndexRef.current === valueIndex) {
      return;
    }
    listRef.current.scrollToIndex({
      index: valueIndex,
      animated: true
    });
  });
  const scheduleSyncScroll = useStableCallback(delay => {
    cancelSyncScroll();
    timeoutId.current = setTimeout(() => {
      timeoutId.current = undefined;
      syncScroll();
    }, delay);
  });
  useEffect(() => cancelSyncScroll, [cancelSyncScroll]);
  useEffect(() => {
    const prevEnabled = prevEnableSyncScrollAfterScrollEnd.current;
    prevEnableSyncScrollAfterScrollEnd.current = enableSyncScrollAfterScrollEnd;
    if (!enableSyncScrollAfterScrollEnd) {
      cancelSyncScroll();
      return;
    }
    if (!prevEnabled && value !== undefined && !isScrollingRef.current) {
      scheduleSyncScroll(SYNC_SCROLL_DELAY_MS);
    }
  }, [cancelSyncScroll, enableSyncScrollAfterScrollEnd, scheduleSyncScroll, value]);
  useEffectWithDynamicDepsLength(() => {
    if (value === undefined) {
      return;
    }
    scheduleSyncScroll(0);
  }, [valueIndex, ...extraValues]);
  const onScrollStart = useStableCallback(() => {
    isScrollingRef.current = true;
    cancelSyncScroll();
  });
  const onScrollEnd = useStableCallback(() => {
    isScrollingRef.current = false;
    if (enableSyncScrollAfterScrollEnd && value !== undefined) {
      scheduleSyncScroll(SYNC_SCROLL_DELAY_MS);
    }
  });
  return {
    onScrollStart,
    onScrollEnd
  };
};
export default useSyncScrollEffect;
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