Convert Vanguard realized lots to the legs of a Beancount transaction. Mostly useful for establishing opening balances given a large set of lots.

vanguard-lots-to-beancount.js

let main = () => {
  const datePattern = new RegExp(`(\\d{2})/(\\d{2})/(\\d{4})`);
  const extractDate = (s) => {
    const m = s.match(datePattern);
    const month = m[1];
    const day = m[2];
    const year = m[3];
    return `${year}-${month}-${day}`;
  };
  const extractLot = (row) => {
    const tds = row.querySelectorAll("td");
    const purchaseDate = extractDate(tds[1].innerText.trim());
    const quantity = tds[4].innerText.trim();
    const cost = tds[5].innerText.trim().substr(1);
    return { purchaseDate, quantity, cost };
  };
  const renderLog =
    (account, units) =>
    ({ purchaseDate, quantity, cost }) => {
      return `${account} ${quantity} ${units} {{ ${cost} USD, ${purchaseDate} }}`;
    };
  const table = document.querySelector("#lots_table tbody");
  const rows = [...table.querySelectorAll("tr")];
  const lots = rows.map(extractLot);
  const resultString = lots
    .map(renderLog("Assets:Vanguard:Taxable:VWSUX", "VWSUX"))
    .join("\n");
  // NOTE: We can't open a top-level frame at a data URL anymore, so the
  // following does not work:
  // const url = `data:text/plain;charset=UTF-8,${encodeURIComponent(resultString)}`;
  // window.open(url, "_blank");
  // Instead, we create an object URL and point the browser at it. For some
  // reason, this _is_ allowed by the browser policy.
  const blob = new Blob([resultString], { type: "text/plain;charset=UTF-8" });
  const url = URL.createObjectURL(blob);
  window.open(url);
};