MTG Mint Card の購入履歴を CSV でダウンロードする

download_mtgcardmint_csv.js

const convertTableToRows = (selector) => {
  const table = document.querySelector(selector);
  const rows = [];
  const headers = Array.from(table.querySelectorAll('tr:first-child th')).map(th => th.innerText);
  rows.push(headers);

  table.querySelectorAll('tr').forEach(tr => {
    const row = [];
    tr.querySelectorAll('td').forEach(td => {
      row.push(td.innerText);
      if (td.colSpan && td.colSpan > 1) {
        row.push(...new Array(td.colSpan - 1).fill(''));
      }
    });

    rows.push(row);
  });

  return rows;
};

const convertRowsToCSV = rows => {
  return rows.map(row => row.map(value => `"${value}"`)).join("\n");
};

const getOrderDate = () => {
  // Get dd element next to td element of Order Date.
  const xpath = "//dt[text()='Order Date']/following-sibling::dd[1]";
  const dd = document.evaluate(xpath, document, null, XPathResult.FIRST_ORDERED_NODE_TYPE, null).singleNodeValue;
  const orderDate = new Date(dd.innerText);

  return orderDate;
};

const downloadCSV = (csv, filename) => {
  const csvFile = new Blob([csv], { type: 'text/csv' });
  const tempLink = document.createElement('a');
  const orderDate = getOrderDate();

  tempLink.style.display = 'none';
  tempLink.download = filename;
  tempLink.href = URL.createObjectURL(csvFile);

  document.body.appendChild(tempLink);

  tempLink.click();

  document.body.removeChild(tempLink);
  
  return filename;
};

const rows = convertTableToRows('table');
const csv = convertRowsToCSV(rows);

const tempLink = document.createElement('a');
const orderDate = getOrderDate();

downloadCSV(csv, `${orderDate.toISOString()}.csv`);

参考

• https://developer.mozilla.org/ja/docs/Web/XPath
• https://developer.mozilla.org/ja/docs/Web/API/URL/createObjectURL
• https://developer.mozilla.org/ja/docs/Web/API/Blob