PressureObserver: PressureObserver() constructor

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

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

The PressureObserver() constructor creates a new PressureObserver object to watch for changes to pressure changes of system resources such as the CPU.

Syntax

js
new PressureObserver(callback)

Parameters

callback

A callback that will be invoked when pressure records are observed. When the callback is invoked, the following parameters are available:

changes

An array containing all PressureRecord objects recorded since the last time the callback was called, or the last time the observer's takeRecords() method was called.

observer

The observer object that is receiving the above records.

Return value

A new PressureObserver object with the specified callback function that will be invoked when PressureObserver.observe() was called to watch pressure changes.

Exceptions

Examples

Log current pressure

This example creates a PressureObserver and takes action whenever there is a pressure change. The sample interval is set to 1000ms, meaning that there will be updates at most every second.

js
function callback(records) {
  const lastRecord = records[records.length - 1];
  console.log(`Current pressure ${lastRecord.state}`);
  if (lastRecord.state === "critical") {
    // disable video feeds
  } else if (lastRecord.state === "serious") {
    // disable video filter effects
  } else {
    // enable all video feeds and filter effects
  }
}

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-pressureobserver-constructor

Browser compatibility

BCD tables only load in the browser