PressureRecord: source property

Limited availabilityAvailable in workersSecure context

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.

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

Browser compatibility