isPromiseLike - API reference

API reference › @evolu/common › Types › isPromiseLike

function isPromiseLike<T>(value: Awaitable<T>): value is PromiseLike<T>;

Defined in: packages/common/src/Types.ts:256

Type guard to check if a value is a PromiseLike.

Use with Awaitable to conditionally await only when necessary, avoiding microtask overhead for synchronous values.

Example

const validate = (id: string): Awaitable<boolean> => {
  const cached = cache.get(id);
  if (cached !== undefined) return cached; // Sync path
  return fetchValidation(id); // Async path
};

const result = validate(id);
const isValid = isPromiseLike(result) ? await result : result;