Add transjakarta-live-data research topic

Verified TransJakarta realtime stack: anonymous MQTT bus feed (wss://mqtt.tj.co.id:8084/mqtt), guest REST API (tijeapi.transjakarta.co.id), official GTFS. Cross-capture verification vs third-party tracker, connection recipes, snapshot tool.

transjakarta-live-data/scripts/tj-snapshot.mjs

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+#!/usr/bin/env node
+// tj-snapshot.mjs — capture a live snapshot of the TransJakarta bus feed (MQTT over WSS).
+//
+// The broker (wss://mqtt.tj.co.id:8084/mqtt) is anonymous. This tool connects,
+// subscribes, and records the last known state of every bus it sees.
+//
+// Setup:  npm install mqtt        (in this directory, or a parent dir)
+// Usage:  node tj-snapshot.mjs [--topic /mobile_armada/#] [--seconds 60] [--out snapshot.json]
+//
+// Output: summary on stdout; with --out, a JSON file:
+//   { capturedAt, durationSec, topic, messages, busCount, buses: { <bus_body_no>: {...} } }
+//
+// Notes: undocumented infrastructure — be gentle; one connection is enough.
+//        Whole fleet: '/mobile_armada/#'. One area: '/mobile_armada/0018-0022/#'.
+
+import mqtt from 'mqtt';
+import fs from 'fs';
+
+const args = process.argv.slice(2);
+const getArg = (name, fallback) => {
+  const i = args.indexOf(name);
+  return i >= 0 && args[i + 1] ? args[i + 1] : fallback;
+};
+
+const topic = getArg('--topic', '/mobile_armada/#');
+const seconds = parseInt(getArg('--seconds', '60'), 10) || 60;
+const outFile = getArg('--out', '');
+
+const out = { capturedAt: new Date().toISOString(), durationSec: seconds, topic, messages: 0, buses: {} };
+
+const client = mqtt.connect('wss://mqtt.tj.co.id:8084/mqtt', {
+  protocolVersion: 4, keepalive: 30, clean: true, connectTimeout: 15000, reconnectPeriod: 0
+});
+
+client.on('connect', () => client.subscribe(topic, { qos: 0 }));
+client.on('error', (e) => console.error('MQTT error:', e.message));
+
+client.on('message', (t, payload) => {
+  out.messages++;
+  try {
+    const d = JSON.parse(payload.toString());
+    if (!d.bus_body_no) return;
+    out.buses[d.bus_body_no] = {
+      lat: d.latitude, lng: d.longitude, bearing: d.bearing,
+      route: d.route_code, trip: d.trip_id, headsign: d.trip_headsign,
+      type: d.type, direction: d.direction,
+      currStop: d.curr_stops, nextStop: d.next_stops,
+      etaNextStopMin: d.estimated_time_next_stops,
+      lastUpdate: d.timestamp, mqttTopic: t
+    };
+  } catch { /* skip malformed */ }
+});
+
+setTimeout(() => {
+  out.busCount = Object.keys(out.buses).length;
+  console.log(`Captured ${out.messages} messages, ${out.busCount} unique buses in ${seconds}s`);
+  if (outFile) {
+    fs.writeFileSync(outFile, JSON.stringify(out));
+    console.log(`Snapshot written to ${outFile}`);
+  }
+  client.end(true);
+  process.exit(0);
+}, seconds * 1000);