vndbtime.user.js

// ==UserScript==
// @name        VNDB Time Flags
// @namespace   https://github.com/MarvNC
// @match       https://vndb.org/v*/lengthvotes
// @grant       none
// @version     1.0
// @author      Marv
// @description Adds language flags to the time votes table.
// @grant       GM_addStyle
// ==/UserScript==

let delayMs = 300;
const vnURL = 'https://vndb.org/v';
const relRegex = /vndb.org\/r\d+/;
const flagHtml = (flag) => `<abbr class="icons lang ${flag}"></abbr>`;

(async function () {
  GM_addStyle(`div.lengthlist .tc5 {
    width: 60px;
}`);

  const vnID = document.URL.match(/vndb\.org\/v([0-9]+)\/lengthvotes/)[1];
  const url = vnURL + vnID;
  let doc = document.createElement('html');
  doc.innerHTML = await getUrl(url);

  const langs = [...doc.querySelectorAll('.mainbox.vnreleases details')];
  const flags = {};
  langs.forEach((elem) => {
    const flag = elem.dataset.saveId.substr(7);
    const releases = [...elem.querySelectorAll('a[href]')]
      .map((elem) => elem.href)
      .filter((href) => href.match(relRegex));
    for (let release of releases) {
      flags[release] = flag;
    }
  });

  console.log(flags);

  [...document.querySelectorAll('a[href]')]
    .filter((elem) => elem.href.match(relRegex))
    .forEach((elem) => {
      const flag = flags[elem.href];
      elem.parentElement.innerHTML = flagHtml(flag) + elem.parentElement.innerHTML;
    });
})();

async function getUrl(url) {
  let response = await fetch(url);
  return await response.text();
}