Function diffUpdate

packages/joint-react/src/utils/diff-update.ts:12–38

(
  original: M,
  diff: Map<K, V>,
  newDataContainKey: (key: K) => boolean
)

 * @description
 */
export function diffUpdate<K, V, M extends Map<K, V>>(
  original: M,
  diff: Map<K, V>,
  newDataContainKey: (key: K) => boolean
): M {
  let hasDelete = false;

  for (const [key] of original) {
    if (!newDataContainKey(key)) {
      original.delete(key);
      hasDelete = true;
    }
  }

  if (diff.size === 0 && !hasDelete) {
    return original;
  }

  const NewMapConstructor = original.constructor as new (entries?: Iterable<[K, V]>) => M;
  const newMap = new NewMapConstructor(original); // shallow copy to preserve type

  for (const [key, value] of diff) {
    newMap.set(key, value);
  }

  return newMap;
}