PressureObserver

{{APIRef("Compute Pressure API")}}{{SeeCompatTable}}{{AvailableInWorkers("window_and_worker_except_service")}}{{securecontext_header}}

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.

Constructor

• {{domxref("PressureObserver.PressureObserver","PressureObserver()")}} {{experimental_inline}}
  • : Creates and returns a new PressureObserver object.

Static properties

• {{domxref("PressureObserver.knownSources_static", "PressureObserver.knownSources")}} {{ReadOnlyInline}} {{experimental_inline}}
  • : Returns an array of {{domxref("PressureRecord.source","source")}} values supported by the user agent.

Instance methods

• {{domxref("PressureObserver.observe","PressureObserver.observe()")}} {{experimental_inline}}
  • : Invokes the pressure observer's callback function when a pressure record for the specified source is observed.
• {{domxref("PressureObserver.unobserve","PressureObserver.unobserve()")}} {{experimental_inline}}
  • : Stops the pressure observer callback from receiving pressure records from the specified source.
• {{domxref("PressureObserver.disconnect","PressureObserver.disconnect()")}} {{experimental_inline}}
  • : Stops the pressure observer callback from receiving pressure records from all sources.
• {{domxref("PressureObserver.takeRecords","PressureObserver.takeRecords()")}} {{experimental_inline}}
  • : Returns the current list of pressure records stored in the pressure observer, emptying it out.

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.

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

{{Specifications}}

Browser compatibility

{{Compat}}

See also

• {{domxref('PerformanceObserver')}}
• {{domxref('MutationObserver')}}
• {{domxref('ResizeObserver')}}
• {{domxref('IntersectionObserver')}}