Question 264559 in Javascript Question posted in
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Javascript – Wakelock.release is not a function. How to release screenlock, non mobile

I am using Javascript on Windows Chrome.

I can successfully set a wakelock and have tested that it does, in fact, prevent my screen from going dark. However, I’m not able to release it. The error I get is

wakeLock.release is not a function

I’ve also tried putting the release code in an async function and using await.

async function set_wakelock() {
    wakeLock = await navigator.wakeLock.request('screen');
    return wakeLock;
}

var wakeLock = set_wakelock();

// alert(wakeLock);  // Correctly shows [Object promise]

try {
    wakeLock.release();
    wakeLock = null;
}  catch (err) {
    alert(err); // wakeLock.release is not a function
}
Tags:

2

Answers


  1. Chosen as BEST ANSWER
    0

    From @derpirscher's comment, I needed to call release() a different way.

    async function set_wakelock() {
    wakeLock = await navigator.wakeLock.request('screen');
    // optional listener:
    wakeLock.addEventListener('release', () => {
         alert('Wake Lock was released');
    }); 
    return wakeLock;
}

function release_wakelock(){
    if  (! wakeLock){
        return;
    }
    try {
        wakeLock.then(wls => wls.release())
        wakeLock = null;
    }  catch (err) {
        // alert(err);
    }
}

var wakeLock = null;
wakeLock =  set_wakelock();
release_wakelock();

// note: should first check that navigator.wakeLock is supported by the browser.

  2. 0

    The set_wakelock is an async method, therefore the immediate return is a promise. Change your code to await for the result

    var wakeLock = await set_wakelock();

    Something like:

    async function set_wakelock() {
  wakeLock = await navigator.wakeLock.request('screen');
  return wakeLock;
}

var wakeLock = await set_wakelock();

// Use the wakelock here...

// Release the wakelock after you have finished using it
await wakeLock.release();
wakeLock = null;
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