Function composedRefCallback

packages/react/src/lib/compose-refs.ts:11–26

(outer: React.Ref<T> | undefined, local: React.RefObject<T | null>)

 */
export const composedRefCallback =
  <T>(outer: React.Ref<T> | undefined, local: React.RefObject<T | null>): React.RefCallback<T> =>
  (node) => {
    local.current = node;
    if (typeof outer === "function") {
      const cleanup = outer(node);
      if (typeof cleanup === "function") {
        return () => {
          local.current = null;
          cleanup();
        };
      }
      return undefined;
    }
    if (outer) outer.current = node;
    return undefined;
  };

/** `composedRefCallback`, kept stable across renders for stable inputs so the
 *  incoming ref is not detached and reattached on every render. */