PressureRecord: source property

Limited availability

This feature is not Baseline because it does not work in some of the most widely-used browsers.

Experimental: This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

Note: This feature is available in Web Workers, except for Service Workers.

Secure context: This feature is available only in secure contexts (HTTPS), in some or all supporting browsers.

The read-only source property is a string indicating the origin source from which the record is coming.

Value

A string indicating the origin source from which the record is coming. The current version of the Compute Pressure API specification supports two main source types:

  • "thermals" represents the global thermal state of the entire system.
  • "cpu" represents the average pressure of the central processing unit (CPU) across all its cores. This state can be affected by other apps and sites than the observing site.

Use the static PressureObserver.knownSources hint to see which source types are supported by your browser. Note that availability can also vary by your operating system and your hardware. Call observe() and check for a NotSupportedError to see if pressure observation is possible.

Examples

Using the source property

In the following example we log the value of the source property in the pressure observer callback.

js
function callback(records) {
  const lastRecord = records[records.length - 1];
  console.log(`Current pressure source: ${lastRecord.source}`);
}

try {
  const observer = new PressureObserver(callback);
  await observer.observe("cpu", {
    sampleInterval: 1000, // 1000ms
  });
} catch (error) {
  // report error setting up the observer
}

Specifications

Specification
Compute Pressure Level 1
# dom-pressurerecord-source

Browser compatibility

desktop mobile
Chrome
Edge
Firefox
Opera
Safari
Chrome Android
Firefox for Android
Opera Android
Safari on iOS
Samsung Internet
WebView Android
WebView on iOS
source
Experimental
Chrome – Full support
Chrome 125 (Release date: 2024-05-14)
footnote Full support
Edge – Full support
Edge 125 (Release date: 2024-05-17)
footnote Full support
Firefox – No support
Firefox
footnote No support
Opera – Full support
Opera 111 (Release date: 2024-06-12)
footnote Full support
Safari – No support
Safari
footnote No support
Chrome Android – No support
Chrome Android
footnote No support
Firefox for Android – No support
Firefox for Android
footnote No support
Opera Android – No support
Opera Android
footnote No support
Safari on iOS – No support
Safari on iOS
footnote No support
Samsung Internet – No support
Samsung Internet
footnote No support
WebView Android – No support
WebView Android
footnote No support
WebView on iOS – No support
WebView on iOS
footnote No support

Legend

Tip: you can click/tap on a cell for more information.

Full support
Full support
No support
No support
Experimental. Expect behavior to change in the future.