What You Will Learn

✓ Node.js Runtime and Module System
✓ The Node.js Event Loop — Deep Dive
✓ Streams and Buffer Management
✓ Express Middleware Architecture
✓ Authentication: JWT and Sessions
✓ Database Integration: PostgreSQL and Redis
✓ Clustering and Worker Threads
✓ Security Best Practices
✓ Testing Node.js Applications
✓ Interview Simulation and Architecture Design

Overview

This 20-hour plan covers the 20% of Node.js that appears in 80% of backend interviews: the event loop, streams, Express/Fastify patterns, clustering, and security. Sessions build from HTTP fundamentals to production architecture. Skipped: Deno, Bun, GraphQL servers, gRPC implementation details, and containerization (covered in DevOps topic). Node.js Runtime and Module System Node.js is a JavaScript runtime built on Chrome's V8 engine. It uses an event-driven, non-blocking I/O model that makes it efficient for I/O-heavy workloads like APIs, microservices, and real-time applications. How Node.js Differs from Browser JavaScript Browser ESM (native) DOM, Web APIs HTML Yes CommonJS (CJS) Modules ES Modules (ESM) The Module Cache Key Built-in Modules Interview Q&A Q: What is the difference between and ? A: is synchronous, evaluates at runtime, and can be called conditionally (inside if statements). is static, evaluated at parse time, and must be at the top level (except dynamic ). uses the CommonJS module system; uses ES Modules. Node.js now supports both, but they cannot be freely mixed — CJS files cannot use , and ESM files use for dynamic imports. Q: What is and ? A: These are CommonJS-specific variables injected into every module. is the absolute path of the directory containing the current file; is the absolute path of the current file itself. They are NOT available in ES Modules — use and the module instead: . Q: Why is the module cache important? A: The module cache ensures that always returns the same object, regardless of how many times it's called. This makes modules behave as singletons — perfect for shared configuration, database connection pools, and shared state. It also prevents re-executing module code on each import, improving startup performance. Common Mistakes Python Implementation

Sample Quiz Questions

1. What are the 6 phases of the Node.js event loop in order?

Understand · Difficulty: 2/5

2. What is the execution order? ```javascript setTimeout(() => console.log('A'), 0); setImmediate(() => console.log('B')); process.nextTick(() => console.log('C')); Promise.resolve().then(() => console.log('D')); ```

Analyze · Difficulty: 4/5

3. What is backpressure in Node.js streams?

Apply · Difficulty: 3/5

+ 28 more questions available in the full app.

Node.js

What You Will Learn

Overview

Sample Quiz Questions

Related Topics

Master Node.js for Your Next Interview