De API gebruiken vanuit Google Sheets

const API_URL = "https://author.trueroyalties.com/api/v1/reports/books";

function importBooks() {
  const key = PropertiesService.getScriptProperties().getProperty(
    "TRUEROYALTIES_API_KEY",
  );
  if (!key) {
    throw new Error("Add TRUEROYALTIES_API_KEY in Project Settings.");
  }

  const rows = [];
  let cursor = null;
  let currency = "";

  while (true) {
    let url = API_URL + "?range=last_30_days&limit=100";
    if (cursor) url += "&cursor=" + encodeURIComponent(cursor);

    const response = UrlFetchApp.fetch(url, {
      headers: { Authorization: "Bearer " + key },
      muteHttpExceptions: true,
    });
    const status = response.getResponseCode();

    // Limit reached: wait as long as the API asks, then retry the same page.
    if (status === 429) {
      const headers = response.getHeaders();
      const wait = Number(headers["Retry-After"] || headers["retry-after"] || 1);
      Utilities.sleep(wait * 1000);
      continue;
    }

    const body = JSON.parse(response.getContentText());
    if (status !== 200) {
      throw new Error(body.code + ": " + body.detail + " (" + body.request_id + ")");
    }

    currency = body.currency;
    for (const line of body.data) {
      rows.push([
        line.book.title,
        line.book.asin,
        line.book.format,
        line.book.marketplace,
        line.units,
        line.revenue,
        line.ad_spend,
        line.net_profit,
        line.tacos === null ? "" : line.tacos,
      ]);
    }

    if (!body.has_more) break;
    cursor = body.next_cursor;
  }

  const spreadsheet = SpreadsheetApp.getActive();
  const sheet =
    spreadsheet.getSheetByName("Books") || spreadsheet.insertSheet("Books");
  sheet.clearContents();
  sheet.getRange(1, 1, 1, 9).setValues([[
    "Title", "ASIN", "Format", "Marketplace", "Units",
    "Royalties (" + currency + ")", "Ad spend", "Net profit", "TACOS",
  ]]);
  if (rows.length > 0) {
    sheet.getRange(2, 1, rows.length, 9).setValues(rows);
  }
}