Appointments for a date range

const BASE = "https://api.healos.ai/ext-api/v1";
const [from, to] = process.argv.slice(2); // YYYY-MM-DD, inclusive, UTC days

async function getPage(date, page) {
  const url = `${BASE}/appointments?date=${date}&limit=100&page=${page}`;
  const res = await fetch(url, { headers: { "X-API-Key": process.env.HEALOS_API_KEY } });
  if (res.status === 429) {
    const wait = Number(res.headers.get("Retry-After") ?? 60);
    await new Promise((r) => setTimeout(r, wait * 1000));
    return getPage(date, page);
  }
  if (!res.ok) throw new Error(`${res.status}: ${(await res.json()).error}`);
  return res.json();
}

const all = [];
for (let d = new Date(`${from}T00:00:00Z`); d <= new Date(`${to}T00:00:00Z`); d.setUTCDate(d.getUTCDate() + 1)) {
  const date = d.toISOString().slice(0, 10);
  for (let page = 1; ; page++) {
    const { data, meta } = await getPage(date, page);
    all.push(...data);
    if (page >= meta.total_pages) break;
  }
}
console.log(`${all.length} appointments`);
for (const a of all) console.log(a.start_at, a.status, a.patient_name, a.appointment_type);