/**
 * Checks if the given value is a valid PropertyKey of an object (`string`, `symbol`, or `number`).
 *
 * @category Objects
 * @example
 * ```typescript
 * isPropertyKey("Lou"); // true
 * isPropertyKey(1); // true
 * isPropertyKey(Symbol("Lou")); // true
 * isPropertyKey({}); // false
 * ```
 * @param input Value to check.
 * @returns `true` if the given value is a valid PropertyKey of an object, `false` otherwise.
 */
export declare const isPropertyKey: (input: unknown) => input is PropertyKey;