perf-marks/dist/esm/perf-marks.js

The simplest and lightweight solution for User Timing API in Javascript.

import { isUserTimingAPISupported } from './is-user-timing-api-supported';
// Map() is not used in order to decrease the bundle
let marksMap = {};
/**
 * Get the current time based on User Timing API or Date
 *
 * @returns number
 *
 */
const getTimeNow = () => {
    if (isUserTimingAPISupported) {
        return performance.now();
    }
    return Date.now ? Date.now() : +new Date();
};
/**
 * Clear marks and measure of performance event
 *
 * @param markName - Performance marker to be checked
 *
 * @returns void
 *
 */
const clear = (markName) => {
    marksMap[markName] = undefined;
    if (!isUserTimingAPISupported) {
        return;
    }
    performance.clearMeasures(markName);
    performance.clearMarks(markName);
};
/**
 * Start performance measure of event
 *
 * @param markName - Performance marker to be started
 *
 * @returns number
 *
 */
const start = (markName) => {
    if (isUserTimingAPISupported) {
        performance.mark(markName);
    }
    marksMap[markName] = getTimeNow();
};
/**
 * Finishes performance measure of event and
 * clear marks and measure if applicable
 *
 * @param markName - Performance marker to be checked
 * @param markNameToCompare - Optional mark to compare to
 *
 * @returns PerfMarksPerformanceEntry
 *
 */
const end = (markName, markNameToCompare) => {
    try {
        const startTime = marksMap[markName];
        if (!isUserTimingAPISupported) {
            return startTime ? { duration: getTimeNow() - startTime, startTime } : {};
        }
        performance.measure(markName, markName, markNameToCompare || undefined);
        const entry = performance.getEntriesByName(markName).pop();
        if (entry) {
            return entry;
        }
        return {};
    }
    catch (e) {
        // If previous mark was missing for some reason, this will throw.
        // This could only happen if something in event loop crashed
        // in an unexpected place earlier.
        // Don't pile on with more errors.
        return {};
    }
    finally {
        // Clear marks immediately to avoid growing buffer.
        clear(markName);
    }
};
/**
 * Clear all marks and measures of performance event
 *
 * @returns void
 *
 */
const clearAll = () => {
    marksMap = {};
    if (!isUserTimingAPISupported) {
        return;
    }
    performance.clearMeasures();
    performance.clearMarks();
};
export { start, end, clear, clearAll };