declare class Headers extends globalThis.Headers { getAll?(key: 'set-cookie'): string[] } declare class Request extends globalThis.Request { readonly headers: Headers readonly duplex: string } declare class Response extends globalThis.Response { readonly headers: Headers static json(data: any, init?: ResponseInit): Response } type RequestInfo = string | Request | globalThis.Request type RequestInit = globalThis.RequestInit declare const fetchImplementation: ( info: RequestInfo, init?: RequestInit ) => Promise declare const FileConstructor: typeof File declare const FormDataConstructor: typeof FormData declare const WebSocketConstructor: typeof WebSocket export { FileConstructor as File, FormDataConstructor as FormData, Headers, Request, RequestInfo, RequestInit, Response, WebSocketConstructor as WebSocket, fetchImplementation as fetch };