JavaScript Asynchronous Programming Quiz

1. The await keyword can only be used inside an async function. True or False?

True

False

2. Which statement best describes the relationship between callbacks and Promises?

Promises are an older alternative to callbacks

Callbacks and Promises serve the same purpose with identical syntax

Promises provide a cleaner way to handle asynchronous operations than callbacks

Callbacks are only used in modern JavaScript

3. A rejected Promise that has no .catch() handler will cause an unhandled rejection error. True or False?

True

False

Submit

5. What is the difference between Promise.all() and Promise.allSettled()?

Promise.all() fails if any promise rejects; allSettled() waits for all to settle

Promise.allSettled() is faster than Promise.all()

Promise.all() handles microtasks; allSettled() handles macrotasks

There is no difference between them

6. Macrotasks in the event loop include setTimeout and setInterval. True or False?

True

False

Submit

8. What is the purpose of the try/catch block in async functions?

To catch syntax errors only

To handle errors from await expressions

To prevent the function from running

To make the function run faster

9. Promise.race() returns the result of whichever promise resolves or rejects first. True or False?

True

False

10. What does Promise.all() do?

Executes promises one after another sequentially

Waits for all promises to settle and returns an array of results

Cancels all pending promises

Converts callbacks to promises automatically

11. What is the primary purpose of asynchronous programming in JavaScript?

To execute code faster than synchronous code

To prevent blocking the main thread while waiting for I/O operations

To automatically handle all errors in the program

To eliminate the need for callbacks

Submit

13. What does async/await syntax do?

Makes asynchronous code look and behave more like synchronous code

Automatically converts all functions to synchronous

Eliminates the need for the event loop

Improves performance by running code in parallel

14. Which method is used to handle errors in a Promise chain?

.catch()

.error()

.fail()

.reject()

15. The .then() method on a Promise returns another Promise. True or False?

True

False

16. A Promise can be in one of three states. Which of the following is NOT a Promise state?

Pending

Fulfilled

Rejected

Paused

17. What is callback hell (or pyramid of doom)?

A JavaScript error that occurs in callbacks

Deeply nested callbacks that reduce code readability

A feature that prevents callbacks from working

An automatic optimization in modern browsers

18. A callback function is passed as an argument to another function. True or False?

True

False

19. What does the event loop do in JavaScript?

Executes all code in a single thread without interruption

Checks the call stack and task queue to determine what code executes next

Prevents asynchronous functions from running

Automatically converts callbacks to promises

20. Which of the following is NOT a way to handle asynchronous operations in JavaScript?

Callbacks

Promises

Async/await

Synchronous loops

JavaScript Institute Asynchronous Programming Quiz

1. The await keyword can only be used inside an async function. True or False?

2.

What first name or nickname would you like us to use?

2. Which statement best describes the relationship between callbacks and Promises?

3. A rejected Promise that has no .catch() handler will cause an unhandled rejection error. True or False?

4. Async/await syntax was introduced to JavaScript in ES____.

5. What is the difference between Promise.all() and Promise.allSettled()?

6. Macrotasks in the event loop include setTimeout and setInterval. True or False?

7. Microtasks include Promises and ____ functions.

8. What is the purpose of the try/catch block in async functions?

9. Promise.race() returns the result of whichever promise resolves or rejects first. True or False?

10. What does Promise.all() do?

11. What is the primary purpose of asynchronous programming in JavaScript?

12. An async function always returns a ____.

13. What does async/await syntax do?

14. Which method is used to handle errors in a Promise chain?

15. The .then() method on a Promise returns another Promise. True or False?

16. A Promise can be in one of three states. Which of the following is NOT a Promise state?

17. What is callback hell (or pyramid of doom)?

18. A callback function is passed as an argument to another function. True or False?

19. What does the event loop do in JavaScript?

20. Which of the following is NOT a way to handle asynchronous operations in JavaScript?