MEAN Node.js Async Patterns and Performance 3

Question 1

What is PM2 and why is it commonly used with Node.js MEAN stack applications?

Accepted Answer

A process manager that keeps Node.js apps running, handles restarts, clustering, and log management

Answer

PM2 is a production process manager that auto-restarts crashed Node.js processes, manages cluster mode for multi-core usage, and provides log aggregation and monitoring.

Question 2

What is the Node.js `--inspect` flag used for?

Accepted Answer

Enables the V8 Inspector protocol for debugging Node.js with Chrome DevTools or VS Code

Answer

The --inspect flag starts Node.js with the V8 Inspector enabled, allowing you to connect Chrome DevTools or an IDE for breakpoint debugging and memory profiling.

Question 3

What does connection pooling do for MongoDB in a Node.js application?

Accepted Answer

Reuses a set of pre-established database connections rather than creating a new one for each query

Answer

Connection pooling maintains a pool of open connections that queries can reuse, avoiding the overhead of establishing a new TCP connection and MongoDB handshake for every operation.

Question 4

What is the purpose of environment variables in a Node.js MEAN application?

Accepted Answer

Store configuration and secrets outside the codebase, accessed via process.env

Answer

Environment variables keep sensitive data like database URLs, API keys, and JWT secrets out of source code, with different values per environment (dev/staging/prod).

Question 5

What is graceful shutdown in a Node.js Express server?

Accepted Answer

Completing in-flight requests before exiting when receiving SIGTERM, preventing abrupt connection drops

Answer

Graceful shutdown listens for SIGTERM, stops accepting new connections, waits for existing requests to complete, then exits — preventing data loss or client errors during deploys.

MEAN - Stack Development Practice Test

MEAN - Stack Development Practice Test

MEAN Node.js Async Patterns and Performance 3