/// <reference types="screeps" />
/** An outdated or not found value from cache */
export type Invalid = Record<string, never> & Tag.OpaqueTag<"Invalid">;
export declare const Invalid: Invalid;
/**
 * Check is {@link v} is not {@link Invalid}.
 * @param v thing to check
 * @returns whether v is found or not
 */
export declare function isValid<V>(v: V | Invalid): v is V;
/**
 * Wrap {@link fn} with a cache indexed by {@link K}.
 * @example sort(ts, cache(t => "heavy compute..."))
 * @param fn function to cache
 * @param getK optional function to extract {@link K} from {@link Ts}
 * @returns cached function
 */
export declare function cache<Ts extends any[], V, K = Ts[0]>(fn: (...ts: Ts) => V, getK: ((...ts: Ts) => K) | (Ts extends [K] ? undefined : never)): (...ts: Ts) => V;
/**
 * Wrap {@link fn} with a cache indexed by {@link K} it is refreshed every given {@link ticks}.
 * @param fn function to cache
 * @param ticks number of ticks to keep
 * @returns cached function
 */
export declare function cacheForTicks<K, V>(fn: (key: K) => V, ticks?: number): (key: K) => V;