import type { Class } from './types.js';
export declare function isPropertyKey(any: unknown): any is PropertyKey;
export declare function isConstructor(fn: unknown): fn is Class<unknown>;
export declare function isFunction(fn: unknown): fn is (...args: unknown[]) => Promise<unknown>;
export declare function isSyncFunction(fn: unknown): fn is (...args: unknown[]) => Promise<unknown>;
export declare function isAsyncFunction(fn: unknown): fn is (...args: unknown[]) => Promise<unknown>;