marky

What is marky?

The marky npm package is a high-resolution JavaScript stopwatch that can be used to measure the duration of operations. It provides an easy-to-use API for starting, stopping, and getting elapsed time with high precision.

What are marky's main functionalities?

Start and stop a timer

This feature allows you to start a timer with a unique name and then stop it later to get the elapsed time.

const marky = require('marky');

marky.mark('myTimer');
// ... some operation ...
const myTimerResult = marky.stop('myTimer');
console.log('Elapsed time:', myTimerResult.duration);

Get a list of all timers

This feature allows you to retrieve a list of all timers that have been created and stopped, including their names and durations.

const marky = require('marky');

marky.mark('timer1');
// ... some operation ...
marky.stop('timer1');

marky.mark('timer2');
// ... another operation ...
marky.stop('timer2');

const allTimers = marky.getEntries();
console.log(allTimers);

Clear all timers

This feature allows you to clear all recorded timers from marky's internal storage.

const marky = require('marky');

marky.mark('timer1');
// ... some operation ...
marky.stop('timer1');

marky.clear();
const allTimersAfterClear = marky.getEntries();
console.log(allTimersAfterClear); // Should be an empty array

Other packages similar to marky

performance-now

This package provides a function to get a timestamp in milliseconds, similar to how performance.now() works in the browser. It is a simpler tool compared to marky, focusing only on getting the current timestamp without the ability to label and store multiple timers.

time-span

time-span is a high-resolution timer that can be used to measure time spans. It offers a simple API to start and end timers, but unlike marky, it does not provide the ability to label timers or retrieve a list of all timers.

README

marky

JavaScript timer based on performance.mark() and performance.measure(), providing high-resolution timings as well as nice Dev Tools visualizations.

For browsers that don't support performance.mark(), it falls back to performance.now() or Date.now(). In Node, it uses process.hrtime().

Quick start

Install via npm:

npm install marky

Or as a script tag:

<script src="https://unpkg.com/marky/dist/marky.min.js"></script>

Then take some measurements:

var marky = require('marky');

marky.mark('expensive operation');
doExpensiveOperation();
marky.stop('expensive operation');

Why?

The User Timing API is more performant than console.time() and console.timeEnd(), and more accurate than Date.now(). Also, you get nice visualizations in Chrome Dev Tools:

As well as Edge F12 Tools:

This is because marky adds standard PerformanceEntries to the Performance Timeline. Tools like WebPageTest and Windows Performance Analyzer also surface them, and you can even send them to your analytics provider.

API

marky.mark() begins recording, and marky.stop() finishes recording:

marky.mark('releaseTheHounds');
releaseTheHounds();
marky.stop('releaseTheHounds');

You can also do more complex scenarios:

function setSail() {
  marky.mark('setSail');
  marky.mark('raiseTheAnchor');
  raiseTheAnchor();
  marky.stop('raiseTheAnchor');
  marky.mark('unfurlTheSails');
  unfurlTheSails();
  marky.stop('unfurlTheSails');
  marky.stop('setSail');
}

marky.stop() also returns a PerformanceEntry:

marky.mark('manTheTorpedos');
manTheTorpedos();
var entry = marky.stop('manTheTorpedos');

The entry will look something like:

{
  "entryType": "measure",
  "startTime": 1974112,
  "duration": 350,
  "name": "manTheTorpedos"
}

You can get all entries using:

var entries = marky.getEntries();

This provides a list of all measures ordered by startTime, e.g.:

[
  {
    "entryType": "measure",
    "startTime": 1974112,
    "duration": 350,
    "name": "numberOne"
  },
  {
    "entryType": "measure",
    "startTime": 1975108,
    "duration": 300,
    "name": "numberTwo"
  },
  {
    "entryType": "measure",
    "startTime": 1976127,
    "duration": 250,
    "name": "numberThree"
  }
]

You can also clear the entries using marky.clear():

marky.clear()

After this, marky.getEntries() will return an empty list. (If the User Timing API is supported, this will delete all the mark and measure entries from the timeline.)

Browser support

marky has been tested in the following browsers/environments:

• IE 9+
• Safari 8+
• iOS 8+
• Android 4.4+
• Chrome
• Firefox
• Edge
• Node 4+

Per the spec, browsers only need to hold a minimum of 150 entries in their Performance Timeline buffer. In older versions of Firefox, the buffer is throttled to 150, which for marky means you can get a maximum of 50 entries from marky.getEntries() (because marky creates two marks and a measure).

If you need to get more than 50 entries from marky.getEntries(), you can do:

if (typeof performance !== 'undefined' && performance.setResourceTimingBufferSize) {
  performance.setResourceTimingBufferSize(10000); // or however many you need
}

In Node and browsers that don't support the User Timing API, marky follows the behavior of Edge and Chrome, and does not limit the number of entries. marky.stop() and marky.getEntries() will return pseudo-PerformanceEntry objects.

See also

• appmetrics.js – a library on top of mark()/measure() which reports to Google Analytics.

Credits

Thanks to @toddreifsteck for feedback on this project and clarifications on the User Timing API.