Global singleton utility function for nextjs. to avoid re-initialization hot reloads

global-singleton.ts

export function globalSingleton<T>(key: string, createInstance: () => T): T {
  const globalStore = globalThis as unknown as Record<string, T | undefined>;
  if (!globalStore[key]) {
    globalStore[key] = createInstance();
  }
  return globalStore[key];
}