This module covers the core programming patterns that make Node.js unique. Unlike other runtimes, Node.js is built around async-first I/O, event-driven communication, streaming data processing, and graceful error recovery. Mastering these concepts is what separates intermediate from senior Node.js developers.

Many developers can write a basic Express API but struggle with:

• Callback hell and Promise chaining
• Building custom event-driven systems
• Processing large files without running out of memory
• Handling errors without crashing the process

This module bridges that gap.

flowchart LR
    Async["2.1 Async Programming"] --> Emitter["2.2 Event Emitter"]
    Emitter --> Streams["2.3 Streams & Buffers"]
    Streams --> Errors["2.4 Error Handling"]
    Errors --> FSDeep["2.5 File System Deep Dive"]
    FSDeep --> Timers["2.6 Timers & Scheduling"]
    Timers --> ChildProc["2.7 Child Processes"]

    style Async fill:#4f46e5,color:#fff
    style Emitter fill:#7c3aed,color:#fff
    style Streams fill:#059669,color:#fff
    style Errors fill:#d97706,color:#fff

• Async Programming Lab
• Stream Processing Lab
• Error Handling Lab

Common interview questions from this module:

• “Explain the Event Loop and async patterns in Node.js”
• “What’s the difference between Promise.all and Promise.allSettled?”
• “How do streams work and what is backpressure?”
• “What’s the difference between operational and programmer errors?”
• “How do you handle errors in async Express routes?”

📄 Full guide: Node.js Interview Questions