import { Metric } from '../types/index';
/**
 * Performantly generate a unique, 30-char string by combining a version
 * number, the current timestamp with a 13-digit number integer.
 * @return {string}
 */
export declare const generateUniqueID: () => string;
export declare const initMetric: <MetricName extends "TTI">(name: MetricName, value?: number) => {
    name: MetricName;
    value: number;
    rating: "good" | "needs-improvement" | "poor";
    id: string;
};
/**
 *
 * @param value number
 * @returns 'good' | 'needs-improvement' | 'poor'
 */
export declare const getRating: (value: number) => Metric['rating'];
/**
 * Check if is's Safari browser.
 * @returns boolean
 */
export declare function isSafari(): boolean;
/**
 * Get the value of the specific search query key.
 * @param name string
 * @returns string
 */
export declare const getQueryString: (name?: string) => string;