Estimo

Estimo is a tool for measuring parse / compile / execution time of javascript.

This tool can emulate CPU throttling, Network conditions, use Chrome Device emulation and more for measuring javascript performance.

Inspired by Size Limit. Thanks @ai and @aslushnikov for support.

Why?

JavaScript is the most expensive part of our frontend.

3.5 seconds to process 170 KB of JS and 0.1 second for 170 KB of JPEG.

• JavaScript Start-up Optimization

• The Cost Of JavaScript In 2018

• The Cost Of JavaScript In 2019

Usage

JS API

const path = require('path')
const estimo = require('estimo')

;(async () => {
  const report = await estimo(path.join(__dirname, '..', 'libs', 'someLib.js'))
  console.log(report)
})()

CLI

estimo -r ./libs/someLib.js

Output

[
  {
    name: string
    parseHTML: number
    styleLayout: number
    paintCompositeRender: number
    scriptParseCompile: number
    scriptEvaluation: number
    javaScript: number
    garbageCollection: number
    other: number
    total: number
  }
]

Fields Description

• name - Resource name (file name or web url).

• parseHTML - Time which was spent for ParseHTML, ParseAuthorStyleSheet events.

• styleLayout - Time which was spent for ScheduleStyleRecalculation, UpdateLayoutTree, InvalidateLayout, Layout events.

• paintCompositeRender - Time which was spent for Animation, HitTest, PaintSetup, Paint, PaintImage, RasterTask, ScrollLayer, UpdateLayer, UpdateLayerTree, CompositeLayers events.

• scriptParseCompile - Time which was spent for v8.compile, v8.compileModule, v8.parseOnBackground events.

• scriptEvaluation - Time which was spent for EventDispatch, EvaluateScript, v8.evaluateModule, FunctionCall, TimerFire, FireIdleCallback, FireAnimationFrame, RunMicrotasks, V8.Execute events.

• javaScript - Time which was spent for both event groups (scriptParseCompile and scriptEvaluation).

• garbageCollection - Time which was spent for MinorGC, MajorGC, BlinkGC.AtomicPhase, ThreadState::performIdleLazySweep, ThreadState::completeSweep, BlinkGCMarking events.

• other - Time which was spent for MessageLoop::RunTask, TaskQueueManager::ProcessTaskFromWorkQueue, ThreadControllerImpl::DoWork events.

• total - Total time.

Additional Use Cases

CPU Throttling Rate

The CPU Throttling Rate Emulation allow you to generate a Performance timeline under specified CPU conditions. To turn on CPU emulation, you must pass the emulateCpuThrottling flag along with additional configuration options.

• emulateCpuThrottling (default: false) - This flag allows the other CPU Throttling Rate options to be respected. They will be completely ignored unless this flag is set.

• cpuThrottlingRate (default: 1) - Sets the CPU throttling rate. The number represents the slowdown factor (e.g., 2 is a "2x" slowdown).

JS API:

await estimo('/path/to/someLib.js', {
  emulateCpuThrottling: true,
  cpuThrottlingRate: 4,
})

CLI:

estimo -r ./libs/someLib.js --cpu --cpuRate 4

Network Emulation

The Network Emulation allow you to generate a Performance timeline under specified network conditions. To turn on network emulation, you must pass the emulateNetworkConditions flag along with additional configuration options.

• emulateNetworkConditions (default: false) - This flag allows the other Network Emulation options to be respected. They will be completely ignored unless this flag is set.

• offline (default: false) - Passing the offline flag to the generate command emulate a network disconnect.

• latency (default: 0) - Artificial, minimum latency between request sent and response header received expressed in milliseconds (ms).

• downloadThroughput (default: 0) - The maximum download speed in megabits per second. 0 disables throttling.

• uploadThroughput (default: 0) - The maximum upload speed in megabits per second. 0 disables throttling.

• connectionType (default: none) - A label of the supposed underlying network connection type that the browser is using. Supported values are documented under Chrome Headless ConnectType documentation. Variants: none, cellular2g, cellular3g, cellular4g, bluetooth, ethernet, wifi, wimax, other.

JS API:

await estimo('/path/to/someLib.js', {
  emulateNetworkConditions: true,
  offline: false,
  latency: 150,
  downloadThroughput: 1.6,
  uploadThroughput: 0.75,
  connectionType: 'cellular3g',
})

CLI:

estimo -r ./libs/someLib.js --net --latency 150 --download 1.6 --upload 0.75 --connection cellular3g

Chrome Device Emulation

The Chrome Device Emulation allow you to generate a Performance timeline under specified device conditions.

• device (default: false) - One of Puppeteer Device Descriptor.

JS API

const report = await estimo('/path/to/someLib.js', {
  device: 'Galaxy S5',
})

CLI

estimo -r ./libs/someLib.js -d Galaxy\ S5

When using CLI, for device names with spaces you should use symbols escaping.

Multiple Resources

JS API

const report = await estimo([
  '/path/to/libs/someLib.js',
  'https://unpkg.com/react@16/umd/react.development.js',
])

CLI

estimo -r /path/to/libs/someLib.js https://unpkg.com/react@16/umd/react.development.js

Pages

You can use all features not only with js files, but with web pages too.

We will wait for navigation to be finished when the load event is fired.

JS API

const report = await estimo('https://www.google.com/')

CLI

estimo -r https://www.google.com/

Time

All metrics in milliseconds.

We are measure system-cpu time. The number of seconds that the process has spent on the CPU.

We not including time spent waiting for its turn on the CPU.

Install

npm i estimo

or

yarn add estimo

How?

It uses puppeteer to generate Chrome Timelines. Which can be transformed in human-readable shape by Tracium.

We will use your local Chrome if it suitable for using with Estimo.

Keep in mind there result depends on your device and available resources.

Who Uses Estimo

• Size Limit

Contributing

Feel free to ask or open an issue.