Browser-timings

Lib for measure client browsers performance. Automatically collects performance data on page load.

Installation

Install npm package

npm i --save @tinkoff/browser-timings

How to

import { browserTimings } from '@tinkoff/browser-timings';

window.addEventListener('load', () => {
  setTimeout(() => {
    // setTimeout is necessary in order to get metrics about loadEventEnd
    const perfData = browserTimings();
  }, 0);
});

After executing perfData will contain client performance metrics which may be send to any external system for further analysis.

Call of the library should be executed only after page load in order to get actual data. Otherwise, it may return empty object without data.

Lib interface

export interface Timings {
  /* Connection timing from client to server */
  connection: number;
  /* How much time backend was preparing response */
  backend: number;
  /* Page download to client */
  pageDownload: number;
  /* Timing of first paint for a page */
  'first-paint': number;
  /* Timing when DOM becomes interactive */
  domInteractive: number;
  /* DOM building is complete */
  domComplete: number;
  /* Page and every resource were loaded */
  pageLoadTime: number;
  /* Common information about resources and its loading time grouped by type */
  download: {
    html: TimingResource;
    js: TimingResource;
    css: TimingResource;
    img: TimingResource;
    font: TimingResource;
    other: TimingResource;
  };
}

interface TimingResource {
  /* Timing of resource loading */
  duration: number;
  /* Byte-size measure of data used by resource */
  encodedDecodeSize: number;
  /* Byte-size measure of data transferred by network. Calculating difference between encodedDecodeSize - transferSize may reveal how much data where stored in browser cache */
  transferSize: number;
}