IdleDetector

The IdleDetector interface of the Idle Detection API provides methods and events for detecting user activity on a device or screen.

This interface requires a secure context.

• IdleDetector() _ : Creates a new IdleDetector object.

• IdleDetector.userStateRead only
  • : Returns a string indicating whether the users has interacted with either the screen or the device since the call to start().
  _ : Returns either "active" to indicate that the user has interacted with the

device within the threshold provided to start() or "idle" if they have not. This attribute returns null before start() is called.

IdleDetector.screenStateRead only

Returns a string indicating whether the screen is locked, one of "locked" or "unlocked". This attribute returns null before start() is called.

change

Called when the value of userState or screenState has changed.

IdleDetector.requestPermission()

Returns a Promise that resolves when the user has chosen whether to grant the origin access to their idle state. Resolves with "granted" on acceptance and "denied" on refusal.

IdleDetector.start()

Returns a Promise that resolves when the detector starts listening for changes in the user's idle state. userState and screenState are given initial values. This method takes an optional options object with the threshold in milliseconds where inactivity should be reported and signal for an AbortSignal to abort the idle detector.

The following example shows creating a detector and logging changes to the user's idle state. A button is used to get the necessary user activation before requesting permission.

const controller = new AbortController();
const signal = controller.signal;

startButton.addEventListener('click', async () => {
  if (await IdleDetector.requestPermission() != "granted") {
    console.error("Idle detection permission denied.");
    return;
  }

  try {
    const idleDetector = new IdleDetector();
    idleDetector.addEventListener('change', () => {
      const userState = idleDetector.userState;
      const screenState = idleDetector.screenState;
      console.log(`Idle change: ${userState}, ${screenState}.`);
    });

    await idleDetector.start({
      threshold: 60_000,
      signal,
    });
    console.log('IdleDetector is active.');
  } catch (err) {
    // Deal with initialization errors like permission denied,
    // running outside of top-level frame, etc.
    console.error(err.name, err.message);
  }
});

stopButton.addEventListener('click', () => {
  controller.abort();
  console.log('IdleDetector is stopped.');
});