import Koa from 'koa';
/**
 * Simple middleware to append CORS response header.
 */
declare type CORSMethod = 'POST' | 'GET' | 'PUT' | 'OPTIONS' | 'PATCH' | 'DELETE';
declare type CORSHeader = 'Authorization' | 'Content-Type';
declare type CORSOptions = {
    origin?: string;
    methods?: CORSMethod[];
    headers?: CORSHeader[];
    maxAge?: number;
};
export default function cors(options?: CORSOptions): Koa.Middleware;
export {};