Window Info is a readable stream that pushes data about windows on screen on MacOS.

Usage no npm install needed!

<script type="module">
  import windowInfo from '';



npm version

window-info is a readable stream that pushes data about windows on screen on MacOS.

It opens a Python process which uses Quartz library to get information about windows.

yarn add -E window-info

Table of Contents


The default exported class is WindowInfo which is a Readable stream.

import WindowInfo from 'window-info'

WindowInfo Stream

WindowInfo is a Readable stream open in object mode with high watermark set to 0 to prevent caching of window data when receiving streams haven't processed previous data. This ensures that the newer data is always as fresh as possible. The presence of the delay value ensures that no data is written before the delay has passed since last write.

  delay?: number = 1000,
): WindowInfo

Create a new stream. The delay argument controls how often to query data.

import { Transform } from 'stream'
import WindowInfo from 'window-info'

(async () => {
  const wi = new WindowInfo({
    delay: 1000,
  let receivedData = 0
  const limit = 1
    .pipe(new Transform({
      transform(data, enc, next) {
        if (receivedData < limit) {
        } else {
          // limit reached
      objectMode: true,
      highWaterMark: 0, // disable receiving buffering
    .pipe(new Transform({
      transform(data, enc, next) {
          ['winid', 'App Name', 'Window Title', 'pid'],
      writableObjectMode: true,
winid App Name Window Title pid
33 SystemUIServer AppleClockExtra 386
73 Avira Item-0 501
60 PostgresMenuHelper Item-0 525
51 Little Snitch Agent Item-0 348
20 SystemUIServer AppleBluetoothExtra 386
24 SystemUIServer AirPortExtra 386
29 SystemUIServer AppleTextInputExtra 386
37 SystemUIServer AppleUser 386
45 Spotlight Item-0 405
18 SystemUIServer Siri 386
16 SystemUIServer NotificationCenter 386
3 Window Server Menubar 177
4292 Visual Studio Code — window-info 367
4291 Visual Studio Code package.json — documentary 367
4171 Google Chrome artdecocode/window-info: Window Info is a readable stream that pushes data about windows on screen on MacOS. 51791
59 iTunes iTunes 382
4 Window Server Backstop Menubar 177
49 Finder 387
41 Dock Desktop Picture - Sierra 2.jpg 384
2 Window Server Desktop 177

destroy(): void

Call the destroy method to kill the underlying python process and end the stream.

Data Type

Each data row in the read chunk contains information about open windows in form of an array.

For example, WindowInfo can generate the following:

  [480, "Code", "example.js — window-info", 405],
  [89, "Google Chrome", "Stream | Node.js v10.2.1 Documentation", 410]

The type definition then is according to the position in the array.

Property Type Description Example
winid number position 0 480
App Name string position 1 Code
Google Chrome
Window Title string position 2 example.js — window-info
Stream | Node.js v10.2.1 Documentation
pid number position 3 405

(c) Art Deco 2018