Questions
4 of 9
1Node js is single-threaded or multithreaded?
2Why is node js single-threaded?
3What are advantages of Node.js Being Single-Threaded?
4How can we simulate multi-threading in node js?
5What is process management?
6Describe fork, spawn and exec.
7Discuss Spawn() method.
8Discuss fork() method.
9Discuss Exec method.
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04 / 09

How can we simulate multi-threading in node js?

Node.js introduced the worker-threads module, which allows you to create threads and execute multiple JavaScript tasks in parallel.

  1. 1

    Once a thread finishes a task, it sends a message to the main thread that contains the result of the operation so that it can be used with other parts of the code.

  2. 2

    The advantage of using worker threads is that CPU-bound tasks don’t block the main thread and you can divide and distribute a task to multiple workers to optimize it.

Difficulty: 6/10
Topics: worker_threads, child_process, event loop

Scenario Questions

0-2 years experience
  1. 1

    We need to offload a CPU‑intensive hash calculation in a small Node script. How would you use the worker_threads API to keep the main event loop responsive?

  2. 2

    If you spawn a child process to run a Python script from Node, what steps do you take to capture its output and handle errors?

2-5 years experience
  1. 1

    You added a Worker to process image thumbnails, but the request latency hasn't improved. What could be causing the main thread to still block?

  2. 2

    During a load test, a burst of requests crashes the Node service when workers are created on demand. How would you redesign the worker usage to avoid this failure?

5-8 years experience
  1. 1

    Design a scalable component that processes video transcoding jobs using a pool of worker_threads. Explain how you would manage job queueing, back‑pressure, and graceful shutdown.

  2. 2

    Your service runs on a Kubernetes cluster and must handle spikes of CPU‑bound work. Compare using a pool of worker_threads versus launching separate containers for each job, and justify your choice.

8+ years experience
  1. 1

    Our legacy monolith uses synchronous file I/O and blocks the event loop. Outline a migration plan to introduce multi‑process or worker‑thread based concurrency across multiple teams while preserving API contracts.

  2. 2

    When introducing a system‑wide worker pool for various services, what cross‑team considerations (monitoring, logging, versioning, resource quotas) do you address to keep the architecture maintainable?

Follow-up Questions

  • ❓What are the memory‑sharing limits between a Worker and the main thread?
  • ❓How would you monitor the health of a pool of workers in production?
  • ❓When might you choose child_process over worker_threads?