import { BindingKey } from '@loopback/core';
import { DataSource } from '@loopback/repository';
import { Response } from '@loopback/rest';
import { PossibleRateLimiter, RateLimitMetadataOptions, RateLimitResult, RateLimitResultWithPoints } from './types';
export declare const noop: () => void;
export declare function toArray<T>(val?: T | T[] | undefined | null): T[];
export declare function isEmpty(val: unknown): boolean;
export declare function isDataSource(ds: unknown): ds is DataSource;
export declare function isBindingKey<T>(selector: unknown): selector is BindingKey<T>;
export declare function isRateLimitMetadataOptions(val: unknown): val is RateLimitMetadataOptions;
export declare function isRateLimitResult(val: unknown): val is RateLimitResult;
export declare function setRateLimitHeaders(response: Response, result: RateLimitResultWithPoints, legacy?: boolean): void;
export declare function getPoints(limiter: PossibleRateLimiter, keyPrefix?: string): number | undefined;