Sort youtube videos by views - channel videos or searched videos

youtube-videos-sorter.js

(() => {
  const channelVideosGrid = document.querySelector('[page-subtype=channels] #items');
  const grid = channelVideosGrid;
  const MULTIPLIER = {
    k: 1000,
    m: 1000 * 1000,
    b: 1000 * 1000 * 1000
  };
  
  if (!grid) {
    throw new Error('It won\'t work on this page.');
  }
  
  const itemSelector = 'ytd-grid-video-renderer';
  const viewSelector = '#metadata-line span:first-child';
  const items = [].map.call(document.querySelectorAll(itemSelector), (item) => {
    const matches = item.querySelector(viewSelector).innerText.match(/([0-9.]+)(K|M)?/i);
    const views = matches[2] ? MULTIPLIER[matches[2].toLowerCase()] * parseInt(matches[1], 10) : parseInt(matches[1], 10);
    
    return {
      item,
      views
    };
  });
  
  if (!items.length) {
    throw new Error('If the list is not empty the CSS selector needs to be updated');
  }
  
  items.sort((a,b) => {
    if (a.views < b.views) return 1;
    if (a.views > b.views) return -1;
    return 0;
  });
  
  items.forEach((item, idx) => {
    grid.appendChild(items[idx].item);
  });
})();