Node.js Interview Questions and Answers | TechIdea

How do you prevent the Node.js event loop from blocking?

You prevent blocking by avoiding synchronous operations (like `fs.readFileSync`) and offloading heavy CPU tasks to Worker Threads or external services.

Deep Dive Explanation

Node.js runs on a single thread. If you execute a massive `while` loop or complex cryptography on that thread, it cannot process any other incoming HTTP requests. To prevent this, you should use asynchronous I/O methods (which offload work to the libuv thread pool) and use Worker Threads (`worker_threads` module) for heavy CPU-bound tasks like image processing or large JSON parsing.

Enterprise Use Case: Imagine an endpoint `/upload-video` that converts a video to MP4. If you run the conversion directly in the main thread, all other users will timeout waiting for your server to respond. Instead, you dispatch the conversion to a Worker Thread or an AWS SQS queue, immediately returning a 'Processing...' status to the user.

💡 Interview Strategy:Don't just say 'use async/await'. Async/await does not magically make a CPU-intensive task non-blocking. It only helps with I/O tasks. Be sure to mention Worker Threads for CPU tasks.

🚨 Common Pitfalls to Avoid:

Using `JSON.parse()` on a 50MB string synchronously, which blocks the event loop for hundreds of milliseconds.

Node.js Interview Questions

How do you prevent the Node.js event loop from blocking?

Deep Dive Explanation

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