Asynchronous JavaScript — Fetch. Await. Master.
Build rock-solid async skills with topic-wise assignments. Each set includes 20 Basic, 20 Intermediate, and 10 Advanced questions so learners move from callbacks to production-ready concurrency, cancellation, and resilience patterns.
Why practice with these assignments?
- Go beyond theory—simulate latency, failures, retries, and streaming.
- Internalize the event loop, task queues, and microtask vs macrotask behavior.
- Master Promises and async/await with real API scenarios and edge cases.
- Prepare for interviews and real projects with tasks that mirror day-to-day work.
How it works
- Pick a topic from the list.
- Attempt questions in order: Basic → Intermediate → Advanced.
- Run in the browser and/or Node; observe with DevTools and logs.
- Add timeouts, retries, and cancellation—then measure outcomes.
- Save your best solutions as portfolio-ready snippets and mini-demos.
What you’ll achieve
- A clear mental model of how JS schedules and runs async tasks.
- Confidence with Promises, async/await, combinators, and cancellation.
- Practical skills for networking, streaming, files, and background work.
- Production habits: timeouts, retries with backoff, idempotency, and tests.
Who should use this page?
JavaScript beginners leveling up, interview candidates, and front-/back-end developers who need dependable async code in apps, APIs, and tooling.
Tips for success
- Prefer async/await for readability; use combinators for structured parallelism.
- Always add timeouts and cancellation—no request should run forever.
- Keep side effects idempotent; guard against duplicate submissions.
- Limit concurrency; queue work and apply backoff on failure.
- Don’t mix callbacks and promises in the same API—wrap once, use consistently.
- Test the sad paths: timeouts, aborts, partial responses, network flakiness.
- Log timings (start/end) to see real-world latency and drift.
Ready to build real confidence in Asynchronous JS? Pick a set below and start solving!
FAQs
Q1. Do I need to know JavaScript before starting?
Yes. You should already be familiar with core JavaScript (variables, functions, arrays, objects) before starting asynchronous tasks.
Q2. Browser or Node?
Both. Topics indicate when a task is browser-only or Node-only—many work in either.
Q3. Do I need a real server?
No. You can use public APIs or mock responses using tools like MSW or Nock. You can also simulate latency and failures locally.
Q4. What topics are covered in these assignments?
Assignments cover callbacks, promises, async/await, event loop, timers, fetch API, error handling, parallel vs sequential execution, and streaming/Node workers.
Q5. How do I verify correctness?
Use DevTools (Network/Performance/Console) or Node logging. Also, apply fake timers and assertions that check timeouts, retries, and cancellation behavior.
Q6. Are there solutions provided?
Yes. Selected topics include reference implementations and alternative approaches. Review them only after attempting the tasks yourself.
Q7. How difficult are these assignments?
Each set includes basic, intermediate, and advanced problems. Beginners can focus on basics first, while advanced learners can explore APIs, workers, and real-world scenarios.
Q8. How much time should I spend per assignment?
Plan 10–40 minutes per difficulty band per topic. More complex tasks like streaming and Node workers may take longer.
Q9. Do I need external libraries?
Not always. Most assignments use vanilla JavaScript. However, some tasks may recommend libraries like Axios for HTTP calls or Jest for testing async behavior.
Q10. Can these assignments help with job interviews?
Absolutely. Asynchronous JavaScript is a core interview topic. Practicing these tasks prepares you for real-world coding tests and technical interviews.