Stops YouTube from automatically pausing the video.

youtube-anti-anti-afk.meta.js

// ==UserScript==
// @name         YouTube - Anti-Anti-AFK
// @namespace    larryc5
// @version      1.0
// @description  Stops YouTube from automatically pausing the video.
// @author       Larry Costigan
// @include      /^https?:\/\/(?:[^\/?#]*\.)?youtube.com\/.*$/
// @downloadURL  https://gist.githubusercontent.com/larryc5/95c3ae2abbd37b35e2a35ac2c49d9996/raw/youtube-anti-anti-afk.user.js
// @updateURL    https://gist.githubusercontent.com/larryc5/95c3ae2abbd37b35e2a35ac2c49d9996/raw/youtube-anti-anti-afk.meta.js
// ==/UserScript==

youtube-anti-anti-afk.user.js

// ==UserScript==
// @name         YouTube - Anti-Anti-AFK
// @namespace    larryc5
// @version      1.0
// @description  Stops YouTube from automatically pausing the video.
// @author       Larry Costigan
// @include      /^https?:\/\/(?:[^\/?#]*\.)?youtube.com\/.*$/
// @downloadURL  https://gist.githubusercontent.com/larryc5/95c3ae2abbd37b35e2a35ac2c49d9996/raw/youtube-anti-anti-afk.user.js
// @updateURL    https://gist.githubusercontent.com/larryc5/95c3ae2abbd37b35e2a35ac2c49d9996/raw/youtube-anti-anti-afk.meta.js
// ==/UserScript==

console.log('YouTube anti-anti-AFK: start');
{
  const pathname = '/watch';
  const elemType = document.createElement('video').nodeType;
  const videoSelect = 'video.video-stream';
  
  const pauseHandler = function() {
    console.log('YouTube anti-anti-AFK: pause');
    if (!this.ended && !document.hasFocus()) {
      console.log('YouTube anti-anti-AFK: play');
      this.play();
      const reload = ()=> {
        if (this.paused && !this.ended && !document.hasFocus()) {
          const onload = ()=> {
            this.removeEventListener('loadeddata', onload);
            this.play();
            setTimeout(reload, 5000);
          };
          this.addEventListener('loadeddata', onload);
          this.load();
        }
      };
      setTimeout(reload, 5000);
    }
  };
  
  Array.from(document.querySelectorAll(videoSelect)).forEach(node => {
    console.log('YouTube anti-anti-AFK: found video');
    node.addEventListener('pause', pauseHandler);
  });
  
  new MutationObserver(mutations => {
    if (location.pathname === pathname) {
      mutations.forEach(mutation => {
        mutation.addedNodes.forEach(addedNode => {
          if (addedNode.nodeType === elemType && addedNode.matches(videoSelect)) {
            console.log('YouTube anti-anti-AFK: found video');
            addedNode.removeEventListener('pause', pauseHandler);
            addedNode.addEventListener('pause', pauseHandler);
          }
        });
      });
    }
  }).observe(document.documentElement, {
    childList: true,
    subtree: true,
  });
}