@shopify/flash-list/src/recyclerview/hooks/useMappingHelper.ts

FlashList is a more performant FlatList replacement

import { useCallback } from "react";

import { useRecyclerViewContext } from "../RecyclerViewContextProvider";

/**
 * Returns a function that can help create a mapping key for the items.
 * Useful when doing .map on items to create a list of components.
 * Using this ensures that performance is optimal for FlashList
 */
export const useMappingHelper = () => {
  const recyclerViewContext = useRecyclerViewContext();
  const getMappingKey = useCallback(
    (itemKey: string | number | bigint, index: number) => {
      return recyclerViewContext ? index : itemKey;
    },
    [recyclerViewContext]
  );

  return { getMappingKey };
};