JavaScript Promises and Async/Await Skills Test
This test evaluates your understanding of asynchronous JavaScript, focusing on Promises and the async/await syntax. Master these patterns to write clean, manageable asynchronous code.
- Questions
- 20-30
- Time limit
- 15-45
- Category
- JavaScript Basics
Promises and async/await are essential for handling asynchronous operations like API calls, file reading, and timers. This test helps identify your proficiency in creating, chaining, and managing Promises, as well as using async/await for readable asynchronous code.
- Basic
- Intermediate
- Advanced
This is a demo version of the test. You may attempt up to 3 questions.
This is a demo version of the test. You may attempt up to 3 questions.
This is a demo version of the test. You may attempt up to 3 questions.
Instructions
Read each question carefully before answering. Choose the best possible answer from the provided options. Manage your time wisely; do not spend too long on a single question. Ensure you are in a quiet environment free from distractions. Focus on correctness over speed.
Key Areas
- Creating and resolving Promises
- Chaining .then() and .catch()
- Using Promise.all, Promise.race, Promise.allSettled
- Async function syntax and await operator
- Error handling with try/catch in async functions
- Converting callbacks to Promises
Recommended Preparation
Review the JavaScript event loop, callback patterns, and the differences between synchronous and asynchronous code. Practice refactoring callback hell into promise chains and then into async/await. Understand the static methods of the Promise object.
Examples of Questions
2. How do you convert a callback-based function into a promise?
3. What does async/await syntax simplify in JavaScript?
4. What method is used to handle errors in a promise chain?
5. How do you run multiple promises in parallel?
6. What is the purpose of the finally method?
7. What does await do in an async function?
8. Which is correct: Promise.all or Promise.allSettled?
9. What happens if a promise is rejected and there is no catch?
10. How to simulate a delay with async/await?