Proximity Events Specification: How To Receive Events From Device Proximity Sensors | Hacker Noon

June 10th 2020

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This is an

experimental technology
Check the Browser compatibility table carefully before using this in production.

The proximity events are a handy way to know when a user is close to a device. These events make it possible to react to such a change, for example by shutting down the screen of a smartphone when the user is having a phone call with the device close to their ear.

Note: Obviously, the API requires the device to have a proximity sensor, which are mostly available only on mobile devices. Devices without such a sensor may support those events but will never fire them.

Proximity Events

When the device proximity sensor detects a change between the device and an object, it notifies the browser of that change. When the browser
gets such a notification, it fires a

DeviceProximityEvent

for any change, and a

UserProximityEvent

event in the case of a more rough change.

Once captured, the event object gives access to different kinds of information:

  • The
    DeviceProximityEvent

    event provides an exact match for the distance between the device and the object through its

    value

    property. It also provides the closest and farthest distance the device is able to detect something through its

    min

    and

    max

    properties.

  • The
    UserProximityEvent

    event provides a rough approximation of the distance, expressed through a boolean. The

    UserProximityEvent.near

    property is

    true

    if the object is close or

    false

    if the object is far.

Example

window.addEventListener('userproximity', function(event) {
  if (event.near) {
    // let's power off the screen
    navigator.mozPower.screenEnabled = false;
  } else {
    // Otherwise, let's power on the screen
    navigator.mozPower.screenEnabled = true;
  }
});

Specifications

Browser compatibility

DeviceProximityEvent

UserProximityEvent

See also

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