import { App } from '../app';
import { Method, MiddlewareContext } from '../types';
type OriginFn = (ctx: MiddlewareContext) => string;
type Origin = string | string[] | OriginFn;
/**
 * Cross-Origin Resource Sharing (CORS) configuration object.
 *
 * This type allows flexible control over allowed origins, headers, and methods.
 *
 * Defaults (if a field is omitted):
 * - `methods`: `['DELETE', 'GET', 'HEAD', 'OPTIONS', 'PATCH', 'POST', 'PUT']`
 * - `allowedHeaders`: `['Content-Type', 'Authorization']`
 * - `credentials`: not sent unless explicitly set to `true`
 * - `exposedHeaders`: not set unless provided
 * - `maxAge`: not set unless provided
 */
export type Cors = {
    /**
     * Allowed origin(s). Can be:
     * - a string (exact match)
     * - an string array (any item exact match)
     * - a function that receives the request context and returns a valid origin
     */
    origin: Origin;
    /**
     * Allowed HTTP methods for CORS requests.
     * @default
     * [`DELETE`, `GET`, `HEAD`, `OPTIONS`, `PATCH`, `POST`, `PUT`]
     */
    methods?: Method[];
    /**
     * Allowed headers for incoming requests.
     * @default
     * ['Content-Type', 'Authorization']
     */
    allowedHeaders?: string[];
    /**
     * Headers that can be exposed to the browser.
     * Default: none
     * @default undefined
     */
    exposedHeaders?: string[];
    /**
     * How long the results of a preflight request can be cached (in seconds).
     * Default: not set
     * @default undefined
     */
    maxAge?: number;
    /**
     * Whether to include `Access-Control-Allow-Credentials: true`.
     * Default: not set (credentials will not be sent)
     */
    credentials?: boolean;
};
export declare const cors: (opts: Cors | string | ((ctx: MiddlewareContext) => string)) => App;
export {};