How do I track multiple USPS tracking numbers at once?

curl "https://api.lastscanned.com/v1/track?numbers=YOUR_USPS_NUMBER,1Z000Y770414233027,541270563758" \
  -H "Authorization: Bearer lsk_live_YOUR_KEY"

// node track-list.mjs < numbers.txt > results.csv   (one number per line)
import { stdin } from "node:process";

let text = "";
for await (const chunk of stdin) text += chunk;
const numbers = [...new Set(text.split(/[\s,]+/).map((n) => n.trim().toUpperCase()).filter(Boolean))];
// e.g. YOUR_USPS_NUMBER_1, YOUR_USPS_NUMBER_2

console.log("tracking_number,carrier,status,last_scan_utc,last_scan,location,error");
for (let i = 0; i < numbers.length; i += 35) {
  const batch = numbers.slice(i, i + 35);
  const url = new URL("https://api.lastscanned.com/v1/track");
  url.searchParams.set("numbers", batch.join(","));
  url.searchParams.set("carrier", "usps");
  const res = await fetch(url, { headers: { Authorization: `Bearer ${process.env.LASTSCANNED_KEY}` } });
  if (!res.ok) throw new Error(`${res.status} ${await res.text()}`);
  for (const { trackingNumber, result, error } of (await res.json()).results) {
    const last = result?.events?.[0]; // events are newest first
    const row = [trackingNumber, result?.carrier, result?.status, last?.timestamp, last?.description, last?.location, error?.code];
    console.log(row.map((v) => JSON.stringify(v ?? "")).join(","));
  }
}