BlackList youtube trends channels (Greasemonkey script)

some.js

// ==UserScript==
// @name     Blacklist Youtube Channels
// @version  1
// @grant    GM.setValue
// @grant    GM.getValue
// @include  https://www.youtube.com/*
// ==/UserScript==

const blacklistChannelName = 'BlacklistYoutubeChannels';
var channels = [];

getParent = function(element, localName) {
  if (element) {
    if (element.localName == localName) {
      return element;
    } else {
      return getParent(element.parentNode, localName);
    };
  };
};

removeChannel = function(channelName) {
  let linksSelector = `a[href='/channel/${channelName}'], a[href='/user/${channelName}']`;
  let links = document.querySelectorAll(linksSelector);

  links.forEach(function(el){
    let parent = getParent(el, 'ytd-video-renderer');
    
    if (parent) {
      parent.remove();
    };
  });
};

// Remove blacklisted channels
(async () => {
  channels = await GM.getValue(blacklistChannelName, []);
  console.log('Blacklist Channels:', channels);
  
  for(let idx in channels) {
    removeChannel(channels[idx]);
  };
})();

// Add links
const channelDivs = document.querySelectorAll('ytd-channel-name');
channelDivs.forEach(function(channelDiv){
  if (channelDiv.localName) {
    const linkToChannel = channelDiv.querySelector('a[href^="/channel/"], a[href^="/user/"]')
    if (linkToChannel) {
      const channel = linkToChannel.href.split('/').pop();
      if (channel) {
        let link = document.createElement('a');
        link.onclick = function() {
          (async () => {
            channels.push(channel);
            await GM.setValue(blacklistChannelName, [...new Set(channels)]);
            removeChannel(channel);
          })();
        };
        link.innerHTML=" To BlackList ";
  
        channelDiv.appendChild(link);      
      };
    };
  };
});