AmbientLightSensor

The AmbientLightSensor interface of the Sensor APIs returns the current light level or illuminance of the ambient light around the hosting device.

To use this sensor, the user must grant permission to the 'ambient-light-sensor' device sensor through the Permissions API.

If a feature policy blocks use of a feature it is because your code is inconsistent with the policies set on your server. This is not something that would ever be shown to a user. The Feature-Policy HTTP header article contains implementation instructions.

if ( 'AmbientLightSensor' in window ) {
  const sensor = new AmbientLightSensor();
  sensor.addEventListener('reading', event => {
    console.log('Current light level:', sensor.illuminance);
  });
  sensor.addEventListener('error', event => {
    console.log(event.error.name, event.error.message);
  });
  sensor.start();
}