import { Request } from 'express-serve-static-core';
export declare type Extractor<T> = (request: Request) => T | null;
export declare type ForcedToggleExtractor = (request: Request) => Record<string, boolean>;
export declare const cookieValue: (name: string) => Extractor<string>;
export declare const fromCookie: (name: string) => ForcedToggleExtractor;
export declare const fromHeader: (name: string) => ForcedToggleExtractor;
export declare const fromQueryParam: (name: string) => ForcedToggleExtractor;
/**
 * Fetches forced toggles from a request based on defaults
 */
export declare const defaultForcedTogglesExtractor: ForcedToggleExtractor;