| 1 | How do you use SharedArrayBuffer to share memory directly between Node.js worker threads, and what are the safety considerations? Node.js › Clustering & Worker Threads | Node.js | Clustering & Worker Threads | Advanced |
| 2 | What is the os.cpus() function used for when setting up clustering in a Node.js application? Node.js › Clustering & Worker Threads | Node.js | Clustering & Worker Threads | Beginner |
| 3 | How do you pass data between the main thread and a worker thread using postMessage(), and what are the limits on what can be sent? Node.js › Clustering & Worker Threads | Node.js | Clustering & Worker Threads | Intermediate |
| 4 | What is the difference between the number of CPU cores and the optimal number of cluster workers for a given Node.js application? Node.js › Clustering & Worker Threads | Node.js | Clustering & Worker Threads | Intermediate |
| 5 | What is the difference between spawning a Worker Thread and spawning a Child Process for running a CPU-intensive JavaScript function? Node.js › Clustering & Worker Threads | Node.js | Clustering & Worker Threads | Intermediate |
| 6 | How do you gracefully terminate a worker thread, and what's the difference between worker.terminate() and letting it exit naturally? Node.js › Clustering & Worker Threads | Node.js | Clustering & Worker Threads | Intermediate |
| 7 | What is a worker thread pool, and why would you build one rather than creating a new Worker for every task? Node.js › Clustering & Worker Threads | Node.js | Clustering & Worker Threads | Advanced |
| 8 | How do you handle an uncaught exception inside a specific cluster worker without taking down the entire application? Node.js › Clustering & Worker Threads | Node.js | Clustering & Worker Threads | Advanced |
| 9 | What is the WorkerData option when creating a Worker, and how does it differ from communicating via postMessage() after creation? Node.js › Clustering & Worker Threads | Node.js | Clustering & Worker Threads | Advanced |
| 10 | What is the difference in behavior between the 'primary' and 'worker' role in Node's cluster module regarding which code paths execute? Node.js › Clustering & Worker Threads | Node.js | Clustering & Worker Threads | Advanced |
| 11 | Why does Node.js provide a cluster module, given that a single Node.js process is single-threaded? Node.js › Clustering & Worker Threads | Node.js | Clustering & Worker Threads | Intermediate |
| 12 | How does PM2's cluster mode compare to manually using Node's built-in cluster module directly in application code? Node.js › Clustering & Worker Threads | Node.js | Clustering & Worker Threads | Intermediate |
| 13 | What is the difference between the 'sticky' and default load-balancing strategies when using Node's cluster module, and when does it matter? Node.js › Clustering & Worker Threads | Node.js | Clustering & Worker Threads | Intermediate |
| 14 | What happens to in-memory state (like an in-memory cache) when using the Node.js cluster module, and how do you handle this correctly? Node.js › Clustering & Worker Threads | Node.js | Clustering & Worker Threads | Advanced |
| 15 | How does zero-downtime restart work with Node's cluster module or PM2, and why is it important for production deployments? Node.js › Clustering & Worker Threads | Node.js | Clustering & Worker Threads | Advanced |
| 16 | How does Node.js implement the Worker Threads module differently from Child Processes, and when should each be used? Node.js › Advanced Node.js | Node.js | Advanced Node.js | Advanced |
| 17 | What is the difference between concurrency and parallelism, and which one does Node.js's event loop actually provide by default? Node.js › Event Loop & Non-blocking IO | Node.js | Event Loop & Non-blocking IO | Beginner |
| 18 | What problem does PM2 solve for running a Node.js application in production, beyond just executing 'node server.js'? Node.js › Deployment & Process Managers (PM2) | Node.js | Deployment & Process Managers (PM2) | Beginner |
| 19 | What is a cron job, and how would you schedule recurring background tasks in a Node.js application using node-cron or BullMQ's repeatable jobs? Node.js › Background Jobs & Queues | Node.js | Background Jobs & Queues | Intermediate |
| 20 | What is a 'stalled' job in BullMQ, and what causes it? Node.js › Background Jobs & Queues | Node.js | Background Jobs & Queues | Intermediate |
| 21 | How does the event loop handle a large synchronous loop (like processing a huge array with a for loop), and what problem does this cause? Node.js › Event Loop & Non-blocking IO | Node.js | Event Loop & Non-blocking IO | Intermediate |
| 22 | What is Redis Pub/Sub, and how would a Node.js application use it to broadcast real-time events across multiple server instances? Node.js › Caching with Redis | Node.js | Caching with Redis | Intermediate |
| 23 | How do you detect and prevent event loop blocking in a long-running Node.js service? Node.js › Advanced Node.js | Node.js | Advanced Node.js | Advanced |
| 24 | What is horizontal scaling for a Node.js application, and what specific architectural requirement does it impose? Node.js › Cloud & DevOps | Node.js | Cloud & DevOps | Advanced |
| 25 | What is the difference between how Node.js handles I/O-bound concurrency versus CPU-bound work, and why does this distinction shape Node.js's ideal use cases? Node.js › Event Loop & Non-blocking IO | Node.js | Event Loop & Non-blocking IO | Advanced |
| 26 | How would you generate a video thumbnail in Node.js using ffmpeg via a library like fluent-ffmpeg? Node.js › File Uploads & Media Processing | Node.js | File Uploads & Media Processing | Advanced |
| 27 | How does Node.js achieve high concurrency for I/O-bound workloads despite running JavaScript on a single main thread? Node.js › Node.js Fundamentals & Runtime Architecture | Node.js | Node.js Fundamentals & Runtime Architecture | Advanced |