Function useDeepMemo

packages/react-aria/src/utils/useDeepMemo.ts:17–27

(value: T, isEqual: (a: T, b: T) => boolean)

import {useRef} from 'react';

export function useDeepMemo<T>(value: T, isEqual: (a: T, b: T) => boolean): T {
  // Using a ref during render is ok here because it's only an optimization – both values are equivalent.
  // If a render is thrown away, it'll still work the same no matter if the next render is the same or not.
  let lastValue = useRef<T | null>(null);
  if (value && lastValue.current && isEqual(value, lastValue.current)) {
    value = lastValue.current;
  }

  lastValue.current = value;
  return value;
}