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 PressureObserver interface is part of the Compute Pressure API and is used to observe the pressure changes of system resources such as the CPU.


PressureObserver() Experimental

Creates and returns a new PressureObserver object.

Static properties

PressureObserver.knownSources Read only Experimental

Returns an array of source values supported by the user agent.

Instance methods

PressureObserver.observe() Experimental

Invokes the pressure observer's callback function when a pressure record for the specified source is observed.

PressureObserver.unobserve() Experimental

Stops the pressure observer callback from receiving pressure records from the specified source.

PressureObserver.disconnect() Experimental

Stops the pressure observer callback from receiving pressure records from all sources.

PressureObserver.takeRecords() Experimental

Returns the current list of pressure records stored in the pressure observer, emptying it out.


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.

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


Compute Pressure Level 1
# the-pressureobserver-object

Browser compatibility

BCD tables only load in the browser

See also