requestFullscreen is not returning a promise

Question

I'm facing an unexpected behavior and wanted to be sure i'm not missing something before i'm filling a bug.
I've played with requestFullscreen on chrome and firefox and noticed it's not returning a promise like stated in the spec.

Example for webkit:

el.addEventListener('click', () => {
    const p = el.webkitRequestFullScreen();
    p.then(() => {console.log('full screen')});
});

I'm getting:

Uncaught TypeError: Cannot read property 'then' of undefined at HTMLDivElement.el.addEventListener

Same goes for firefox:

el.addEventListener('click', () => {
    const p = el.mozRequestFullScreen();
    p.then(() => {console.log('full screen')});
});

TypeError: p is undefined

Am i reading the spec wrong? shouldn't i expect that promise?

Solution

https://developer.mozilla.org/en-US/docs/Web/API/Element/requestFullScreen#Browser_compatibility

Unfortunately there's no browser support for the promise-returning version.

Comments

[Kaiido]

Ah... the [moz|webkit|o|ms]Full[s|S]creen API... That's just a mess. You shouldn't expect anything than nightmares trying to make a cross-browser code... But yes, according to specs that's what should be returned. But since nobody follows the specs there, we don't have it. FF has a 3 yo bug-report about it, currently P5... For their defense, they keep the prefixed version exactly because they don't follow the specs. On the other hand I couldn't find Chrome's discussion about it, and they did map to unprefixed method...

[Sagiv b.g]

@Kaiido thanks, been looking for that bug but had no luck finding it.

[nh2]

These docs are currently wrong for Chrome. It says version 71 doesn't support the promise version, but it does. I've researched it: The change that added the promise-returning version to Chromium landed in Chromium 69.0.3446.0.