Force video pause on space

force-video-pause.user.js

/*
Pressing space key should pause videos, but many streaming sites fail to
implement that correctly, so attempt to fix it. Highly experimental.

Copyright 2022 Josiah Ulfers
This work is free. You can redistribute it and/or modify it under the
terms of the Do What The Fuck You Want To Public License, Version 2,
as published by Sam Hocevar. See http://www.wtfpl.net/ for more details.
*/
// ==UserScript==
// @name        Force video pause on space
// @namespace   http://josiahulfers.com/force-video-pause
// @version     2
// @description Forces spacebar to pause and play videos in fullscreen
// @updateURL   https://gist.githubusercontent.com/julfers/05f3631b34e8790c3b466c8c14a1108c/raw/force-video-pause.user.js
// ==/UserScript==

function blockFullscreenKey(key, fn) {
    return function (keyEvent) {
        if (keyEvent.key != ' ') return

        let fse = document.fullscreenElement,
            vid = fse && fse.querySelector('video')
        if (vid) {
            keyEvent.stopImmediatePropagation()
            keyEvent.preventDefault()
            fn && fn(vid)
        }
    }
}

function togglePause(video) {
    if (video.paused) video.play()
    else video.pause()
}

window.addEventListener('keydown', blockFullscreenKey(' '), true)
window.addEventListener('keypress', blockFullscreenKey(' '), true)
window.addEventListener('keyup', blockFullscreenKey(' ', togglePause), true)