Explore JavaScript Promises and Async/Await: Exercises with Solutions

JavaScript Promises and Async/Await [20 exercises with solutions]

Create a Simple Promise:

1. Write a JavaScript function that returns a Promise that resolves with a "Hello, World!" message after 1 second.

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Promise Chain Example:

2. Write a JavaScript function that uses a chain of .then() calls to perform a series of asynchronous tasks.

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Handling Promise Rejection:

3. Write a JavaScript program that demonstrates how to catch and handle errors in Promises using .catch().

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Promise.any() Example:

4. Write a JavaScript function that takes multiple Promises and resolves with the first successful result using Promise.any().

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Promise.allSettled() Example:

5. Write a JavaScript program that takes an array of Promises and logs both resolved and rejected results using Promise.allSettled().

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Simulating a Task Queue:

6. Write a JavaScript program that processes an array of asynchronous tasks sequentially using Promises.

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Chained Async/Await Example:

7. Write a JavaScript program that uses async/await to perform three asynchronous tasks in sequence.

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Error Handling in Async/Await:

8. Write a JavaScript program to demonstrate how to handle errors in async/await functions using try...catch.

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Simulating a Throttled API:

9. Write a JavaScript function that ensures only a specified number of asynchronous requests are made simultaneously.

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Custom Promise Wrapper:

10. Write a JavaScript function that wraps an asynchronous operation in a Promise.

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Promise with setTimeout:

11. Write a JavaScript function that creates a Promise that resolves after a given number of milliseconds.

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Promise.all with Mixed Operations:

12. Write a JavaScript program that combines synchronous and asynchronous tasks using Promise.all.

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Creating a Debounce Function:

13. Write a JavaScript function that creates a debounce function using Promises and setTimeout.

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Async/Await with Dynamic Imports:

14. Write a JavaScript program that dynamically imports a module and uses an async function from that module.

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Promise.race Exercise:

15. Write a JavaScript program that demonstrates the use of Promise.race to return the first completed Promise.

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Handling Nested Promises:

16. Write a JavaScript function that resolves a nested Promise structure using async/await.

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Simulating a Loading Spinner:

17. Write a JavaScript program that displays a "loading" message while waiting for an async operation to complete.

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Cancelable Promise:

18. Write a JavaScript function that creates a cancellable Promise by using a custom wrapper.

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Parallel vs Sequential Fetch:

19. Write a JavaScript program to fetch data from multiple APIs first in parallel and then sequentially, comparing their performance.

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Chained Retry with Delays:

20. Write a JavaScript program to implement a function that retries a failed asynchronous operation with increasing delays between attempts.

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Live Demo:

See the Pen javascript-common-editor by w3resource (@w3resource) on CodePen.

Do not submit any solution of the above exercises at here, if you want to contribute go to the appropriate exercise page.