Show flat prices on eBay Kleinanzeigen as price per square meter

ebay-kleinanzeigen-flat-m2.js

// ==UserScript==
// @name         Price Per Square Meter
// @namespace    http://tampermonkey.net/
// @version      0.1
// @description  Display price per square meter
// @author       You
// @match        https://www.ebay-kleinanzeigen.de/s-wohnung-kaufen/*
// @match        https://www.ebay-kleinanzeigen.de/s-auf-zeit-wg/*
// @match        https://www.ebay-kleinanzeigen.de/s-immobilien/*
// @match        https://www.ebay-kleinanzeigen.de/s-wohnung-mieten/*
// @grant        none
// ==/UserScript==

(function() {
  'use strict';

  const $resList = document.querySelectorAll(".aditem");
  for (let $resEntry of $resList) {
      const $tags = $resEntry.querySelectorAll(".tag-small");
      const $area = $tags ? Array.from($tags).find(tag => tag.textContent.includes("m²")) : null;
      const $price = $resEntry.querySelector(".aditem-main--middle--price");

      if ($area == null || $price == null) {
          continue;
      }

      const price = $price.textContent.trim().replace(" €", "").replace(".", "");
      const area = $area.textContent.trim().replace("  m²", "").replace(".", "").replace(",", ".");
      const result = parseFloat(price) / parseFloat(area);

      const $patch = document.createElement("span");
      $patch.style = "color: red; margin-left: 1em;";
      $patch.textContent = `${result.toFixed(0)} €/m²`;

      $price.appendChild($patch);
  }
})();