export declare const performance: Performance;
export declare const timing: PerformanceTiming;
export type PerfTimingKey = keyof Omit<PerformanceTiming, "toJSON">;
export declare function navigationType(): number | "";
/**
 * Returns the delivery type for the current document. To differentiate between the valid empty
 * string value and browsers that don't support PerformanceResourceTiming.deliveryType, we convert
 * the empty string value to "(empty string)". Browsers that don't support deliveryType will return
 * null. Despite straying from the spec, this allows us to differentiate between the two cases.
 *
 * @see https://w3c.github.io/resource-timing/#dom-performanceresourcetiming-deliverytype
 */
export declare function deliveryType(): string | undefined;
export type PolyfilledNavigationTiming = Partial<PerformanceNavigationTiming> & {
    [key: string]: number | string;
    navigationStart: number;
    activationStart: number;
    startTime: number;
    type: PerformanceNavigationTiming["type"];
};
export declare function getNavigationEntry(): PolyfilledNavigationTiming;
/**
 * Simple wrapper around performance.getEntriesByType to provide fallbacks for
 * legacy browsers, and work around edge cases where undefined is returned instead
 * of an empty PerformanceEntryList.
 */
export declare function getEntriesByType(type: string): PerformanceEntryList;
/**
 * Simple wrapper around performance.getEntriesByName to provide fallbacks for
 * legacy browsers, and work around edge cases where undefined is returned instead
 * of an empty PerformanceEntryList.
 */
export declare function getEntriesByName(type: string): PerformanceEntryList;