HOWTO.md

How to experiment ComputePressure API with Chrome

The Compute Pressure API is currently available in Chrome Canary and Edge Canary behind a flag.

Own local Chromium repository (Linux):

1. Rebase to latest HEAD and compile the chromium project.
2. Launch Chrome with the command line flag --enable-features=ComputePressure.
3. Navigate to about://flags and enable Experimental Web Platform features.
4. Navigate to the demo page, https://w3c.github.io/compute-pressure/demo/.
5. Play with the demo.

Chrome/Edge Canary (Windows Only):

1. Download a version of Chrome with ComputePressure implemented (Chrome Canary) (Edge Canary).
2. Find your Canary browser in the menu.
   
   
3. Click right and select "properties".
   
   
4. Add to the command line flags --enable-features=ComputePressure. (after the last ")
   
   
5. Start your browser.
6. Navigate to about://flags and enable Experimental Web Platform features.
7. Navigate to the demo page, https://w3c.github.io/compute-pressure/demo/.
8. Play with the demo.

Code Examples:

// Observer Callback.
function pressureObserverCallback(updates) {
  console.log("cpu pressure state = " + updates[0].state);
  console.log("timestamp = " + updates[0].time);
}

// Create observer with 1000ms sample interval.
observer = new PressureObserver(pressureObserverCallback);

// Start observer.
await observer.observe("cpu", { sampleInterval: 1_000 });

You should see, everytime the state changes, the following:

cpu pressure state = nominal
timestamp = 1671114838027.834

cpu pressure state = serious
timestamp = 1671114914289.584

cpu pressure state = critical
timestamp = 1671114926328.48

Stopping observer:

// Stop observer.
observer.unobserve('cpu');

Other API calls and examples can be found in the specification.