WakeLock: request() method

{{APIRef("Screen Wake Lock API")}}{{SecureContext_Header}}

The request() method of the {{domxref("WakeLock")}} interface returns a {{jsxref("Promise")}} that fulfills with a {{domxref("WakeLockSentinel")}} object if the system screen wake lock is granted.

The screen wake lock prevents device screens from dimming or locking when an application needs to keep running.

Syntax

request(type)

Parameters

• type {{optional_inline}}
  • : A string specifying the screen wake lock type, from among the following enumerated types:
    • screen
      • : Prevents the screen from turning off. Only visible documents can acquire the screen wake lock.

If no type parameter is explicitly specified, the request() method defaults to using the screen type.

Return value

A {{jsxref("Promise")}} that resolves with a {{domxref("WakeLockSentinel")}} object.

Exceptions

• NotAllowedError {{domxref("DOMException")}}
  • : Thrown when wake lock is not available, which can happen because:
    • Use of this feature is blocked by a Permissions Policy.
    • The document is not fully active.
    • The document's visibility state is hidden.
    • The {{Glossary("User Agent")}} could not acquire platform's wake lock. For example, this might happen if the device is low on battery.

Examples

The following asynchronous function requests a {{domxref("WakeLockSentinel")}} object. The request() method is wrapped in a try...catch statement to handle cases where the browser refuses the request for any reason.

const requestWakeLock = async () => {
  try {
    const wakeLock = await navigator.wakeLock.request("screen");
  } catch (err) {
    // The wake lock request fails - usually system-related, such as low battery.

    console.log(`${err.name}, ${err.message}`);
  }
};

requestWakeLock();

The screen wake lock may be revoked by the device after it has been granted. The returned {{domxref("WakeLockSentinel")}} can be used to check the status of the lock, and/or to manually cancel a held screen wake lock.

Specifications

{{Specifications}}

Browser compatibility

{{Compat}}

See also

• Stay awake with the Screen Wake Lock API