wakeLock

Prevents the screen from sleeping. Auto-reacquire when the tab returns to the foreground.

Module wakeLock | Source packages/front/fw/src/dom/lifecycle/wakeLock.js | Deps visibility | Worker-safe no

Wrapper around navigator.wakeLock.request('screen'). The spec auto-releases the wake lock when the tab goes hidden — this module handles auto-reacquire when the tab becomes visible again (option reacquireOnVisible: true, default).

Resolve

const wakeLock = runtime.resolve('wakeLock');
// Returns: { isSupported, acquire }

API

Options acquire

{ reacquireOnVisible: true }  // (default) re-acquire after returning to visible

Type Lock

lock.released                  // boolean — true after release
lock.onRelease(callback)       // called on release — returns unsubscribe
await lock.release()           // manually releases, cleans up visibility listeners

Examples

Video player / GPS navigation

const wakeLock = runtime.resolve('wakeLock');

if (!wakeLock.isSupported()) {
    console.warn('Wake Lock not supported');
}

const lock = await wakeLock.acquire(); // reacquireOnVisible: true by default

// Cleanup when leaving the feature
document.querySelector('#stop-btn').onclick = async () => {
    await lock.release();
};

Without auto-reacquire

const lock = await wakeLock.acquire({ reacquireOnVisible: false });
lock.onRelease(() => console.log('Screen wake lock released'));

Multiple independent locks

const lock1 = await wakeLock.acquire(); // video player
const lock2 = await wakeLock.acquire(); // GPS navigation

// Release independently
await lock1.release(); // GPS continues
await lock2.release(); // all released

Notes

• Wake lock auto-released by the browser when the tab goes hidden (spec). reacquireOnVisible: true automatically re-acquires when document.visibilityState becomes visible again.
• HTTPS required except localhost.
• Type 'screen' only — 'system' is not supported in a browser context.
• release() removes visibility listeners and notifies onRelease callbacks.
• Use cases: video player, GPS navigation, presentation, games. Always release() as soon as possible — battery drain.

See also

• visibility — manages auto-reacquire internally
• idle — detect user inactivity