/**
 * Class TailUtil
 */
export default class TailUtil {
    private url;
    private options;
    constructor(url: string, options: any);
    connect(filters: any, keys: string[] | undefined, cb: (x: string) => void): void;
    /**
     * Filter json output
     * @param {string} json
     * @param {any} filters
     * @return {string|null}
     */
    filterOutput(json: string, filters: any, keys?: string[]): string | null;
    /**
     * Format queue messange json
     * @param {string} json
     * @return {string}
     */
    formatJsonOutput(json: any, keys?: string[]): string;
}