Debug: Node.js memory leak detection

Node.js process memory keeps growing over time, eventually crashing with heap out of memory error.

Step-by-step memory leak detection:

1. Monitor memory usage:

setInterval(() => {
const used = process.memoryUsage();
console.log(Heap: ${(used.heapUsed / 1024 / 1024).toFixed(1)} MB);
}, 10000);

1. Take heap snapshots:

node --inspect app.js
# Open chrome://inspect, take heap snapshots
# Compare two snapshots to find growing objects

1. Common leak sources:

- Event listeners not removed: emitter.on() without off()
- Closures holding references to large objects
- Growing arrays/maps used as caches without eviction
- Timers not cleared: setInterval without clearInterval
- Global variables accumulating data

1. Programmatic heap dump:

const v8 = require('v8');
const fs = require('fs');
const snapshotStream = v8.writeHeapSnapshot();
// Generates .heapsnapshot file, load in Chrome DevTools

1. Use --max-old-space-size to control crash point:

node --max-old-space-size=512 app.js

1. Tools: clinic.js, memwatch-next, heapdump npm packages