/**
 * @license
 * Copyright Google LLC All Rights Reserved.
 *
 * Use of this source code is governed by an MIT-style license that can be
 * found in the LICENSE file at https://angular.io/license
 */
/**
 * Joins two parts of a URL with a slash if needed.
 *
 * @param start  URL string
 * @param end    URL string
 *
 *
 * @returns The joined URL string.
 */
export declare function joinWithSlash(start: string, end: string): string;
/**
 * Removes a trailing slash from a URL string if needed.
 * Looks for the first occurrence of either `#`, `?`, or the end of the
 * line as `/` characters and removes the trailing slash if one exists.
 *
 * @param url URL string.
 *
 * @returns The URL string, modified if needed.
 */
export declare function stripTrailingSlash(url: string): string;
/**
 * Normalizes URL parameters by prepending with `?` if needed.
 *
 * @param  params String of URL parameters.
 *
 * @returns The normalized URL parameters string.
 */
export declare function normalizeQueryParams(params: string): string;