/**
 * 🎯 Decorator `@cached` caches every unique (args -> result) pair
 * on a per-instance basis. Subsequent calls with the same arguments
 * return the cached result (instant for sync, same Promise for async).
 *
 * A static `cached.invalidate(fn)` method allows clearing the cache
 * for a given method/field so that subsequent calls re-invoke the original.
 *
 * Usage:
 * ```typescript
 * class Example {
 *   @cached sum(a: number, b: number): number {
 *     return a + b;
 *   }
 * }
 *
 * const e = new Example();
 * e.sum(1, 2); // computes 3
 * e.sum(1, 2); // returns 3 from cache
 *
 * // flush the cache for this method
 * cached.invalidate(e.sum);
 * ```
 */
export declare function cached(ttl: number): {
    <A extends Array<unknown>, R>(value: unknown, context: ClassMethodDecoratorContext<object, (...args: A) => R>): (...args: A) => R;
    <A extends Array<unknown>, R>(value: unknown, context: ClassFieldDecoratorContext<object, (...args: A) => R>): (originalFn: (...args: A) => R) => (...args: A) => R;
};
export declare function cached<A extends Array<unknown>, R>(value: unknown, context: ClassMethodDecoratorContext<object, (...args: A) => R>): (...args: A) => R;
export declare function cached<A extends Array<unknown>, R>(value: unknown, context: ClassFieldDecoratorContext<object, (...args: A) => R>): (originalFn: (...args: A) => R) => (...args: A) => R;
export declare namespace cached {
    var invalidate: (target: Function) => void;
}