Q44: What are common causes of memory leaks in Express applications and how do you prevent them?
Common memory leak causes include:
- Unbounded in-memory arrays acting as caches.
- Event listeners added inside request middleware without being removed.
- Unclosed database cursors or connection pools.
- Storing session data in-memory (
MemoryStore) in production environments.
Key Takeaways
- Never use default
MemoryStorefor sessions in production; use Redis or database session stores. - Monitor process heap growth using heap dumps and tools like Chrome DevTools or clinic.js.