import type { AnyAsyncMiddleware, ErrorMiddleware, ErrorMiddlewareAsync, MiddlewareAsync, MiddlewarePromise, OptionsResponse } from './shared.js';
export interface ExtendableIndexedMiddleware<T extends unknown[]> {
}
/**
 * MiddlewareIndexedAsync class that implements MiddlewareAsync and ExtendableIndexedMiddleware.
 * @template T - The type of the arguments.
 * @template TMiddleware - The type of the middleware.
 */
export declare class MiddlewareIndexedAsync<T extends unknown[], TMiddleware extends AnyAsyncMiddleware<T>> implements MiddlewareAsync<T>, ExtendableIndexedMiddleware<T> {
    private getIndexKey;
    readonly name?: string;
    protected _delegate: MiddlewareAsync<T>;
    /**
     * Constructor for MiddlewareIndexedAsync.
     * @param {function} getIndexKey - Function to get the index key.
     * @param {string} [name] - Optional name for the middleware.
     */
    constructor(getIndexKey: (...args: T) => string, name?: string);
    /**
     * Get the keys of the index.
     * @returns {string[]} The keys of the index.
     */
    protected getKeys(): string[];
    protected readonly index: Record<string, TMiddleware> & {
        ''?: ErrorMiddleware<T>;
    };
    /**
     * Use middleware for a specific key.
     * @param {null|string} key - The key for the middleware.
     * @param {AnyAsyncMiddleware} middleware - The middleware to use.
     * @returns {this} The instance of MiddlewareIndexedAsync.
     */
    useMiddleware(key: null, middleware: MiddlewareAsync<T>): this;
    useMiddleware(key: '', middleware: ErrorMiddlewareAsync<T>): this;
    useMiddleware(key: string, middleware: TMiddleware): this;
    /**
     * Use an error handler.
     * @param {function} handler - The error handler function.
     * @returns {this} The instance of MiddlewareIndexedAsync.
     */
    useError(handler: ((error: Error | OptionsResponse, ...args: T) => Promise<unknown>)): this;
    /**
     * Process the request.
     * @template X - The type of the return value.
     * @param {...T} req - The request arguments.
     * @returns {Promise<X>} The result of the processing.
     */
    process<X = unknown>(...req: T): Promise<X>;
    /**
     * Handle an error.
     * @param {Error|OptionsResponse} error - The error to handle.
     * @param {...T} req - The request arguments.
     * @returns {MiddlewarePromise} The result of the error handling.
     */
    handleError(error: Error | OptionsResponse, ...req: T): MiddlewarePromise;
    /**
     * Handle the request.
     * @param {...T} req - The request arguments.
     * @returns {MiddlewarePromise} The result of the handling.
     */
    handle(...req: T): MiddlewarePromise;
}