export declare class ObjectUtil {
    static deepClone<T>(obj: T): T;
    /**
     * Recursively serialize an object into a query string that can be used in a URL.
     * Example:
     * ```
     * ObjectUtil.serialize({ a: 1, b: { c: 2, d: [3, 4] } })
     * // Returns: 'a=1&b[c]=2&b[d][0]=3&b[d][1]=4'
     * ```
     * @param obj
     * @param prefix
     */
    static serialize(obj: any, prefix?: string): string;
}