User Scripts/Steam History - Calculates the payment history at https://store.steampowered.com/account/history

steam.js

(() => {
  const pattern = new RegExp("https://store.steampowered.com/account/history");

  if (!pattern.test(window.location.href)) {
    return;
  }

  let last;
  const content = (item) =>
    (item.querySelector("div") ?? item).innerText.replace(/\s+/g, " ").trim();
  const calculate = () => {
    const result = Object.entries(
      Array.from(
        document.querySelectorAll(".wallet_history_table tbody tr"),
      ).reduce((groups, tr) => {
        const [, title, , total, change] = Array.from(
          tr.querySelectorAll("td"),
        ).map(content);

        if (title && total && change && /^-/.test(change)) {
          const totalNum = parseInt(
            total.replace(/[^\d,]/g, "").replace(",", "."),
          );

          groups[title] ??= 0;
          groups[title] = (groups[title] ?? 0) + totalNum;
        }

        return groups;
      }, {}),
    )
      .map(([title, amount]) => ({ title, amount }))
      .filter(({ amount }) => amount > 10)
      .sort((a, b) => b.amount - a.amount);
    const dump = JSON.stringify(result);

    if (last === dump) {
      return;
    }

    last = dump;

    console.clear();
    console.table(result);

    return calculate;
  };
  const debounce = (fn, ms = 300) => {
    let timer;

    return (...args) => {
      if (timer) {
        clearTimeout(timer);
      }

      timer = setTimeout(() => fn(...args), ms);
    };
  };
  const calculateFn = debounce(calculate);

  calculate();
  document.body.addEventListener("DOMSubtreeModified", calculateFn);
})();