Function mergeIds

packages/react-aria/src/utils/useId.ts:109–127

(idA: string, idB: string)

 * Different ids will trigger a side-effect and re-render components hooked up with `useId`.
 */
export function mergeIds(idA: string, idB: string): string {
  if (idA === idB) {
    return idA;
  }

  let setIdsA = idsUpdaterMap.get(idA);
  if (setIdsA) {
    setIdsA.forEach(ref => (ref.current = idB));
    return idB;
  }

  let setIdsB = idsUpdaterMap.get(idB);
  if (setIdsB) {
    setIdsB.forEach(ref => (ref.current = idA));
    return idA;
  }

  return idB;
}

/**
 * Used to generate an id, and after render, check if that id is rendered so we know