Module 9 – Asynchronous JavaScript MCQs

1.What does asynchronous JavaScript allow you to do?

a) Run code line by line only
b) Block the browser
c) Run tasks without stopping the main program
d) Stop execution completely

2. What is a Promise in JavaScript?

a) A loop
b) A function
c) An object representing a future value
d) A variable

3. Which states can a Promise have?

a) Start, End
b) Pending, Fulfilled, Rejected
c) Open, Closed
d) True, False

4. Which method runs when a Promise is successful?

a) catch()
b) finally()
c) then()
d) resolve()

5. Which method handles Promise errors?

a) error()
b) stop()
c) catch()
d) fail()

6. Which keyword is used to define an asynchronous function?

a) await
b) promise
c) async
d) delay

7. What does the await keyword do?

a) Stops the browser
b) Waits for a Promise to resolve
c) Creates a Promise
d) Cancels execution

8. Where can the await keyword be used?

a) Anywhere
b) Inside loops only
c) Inside async functions
d) Inside objects only

9. Which API is commonly used to fetch data from a server?

a) DOM API
b) Storage API
c) Fetch API
d) Timer API

10. What does the fetch() function return?

a) Data directly
b) HTML code
c) Promise
d) JSON object

11. Which method converts fetch response to JSON?

a) parse()
b) convert()
c) response.json()
d) JSON.parse()

12. Which project uses Fetch API to search data dynamically?

a) Notes App
b) Movie Search App
c) Calculator
d) Counter

13. A Currency Converter mainly requires:

a) LocalStorage
b) Timers
c) Live API data
d) DOM only

14. Which concept helps avoid “callback hell”?

a) Loops
b) Promises and async/await
c) Variables
d) Arrays

15. Asynchronous JavaScript is mainly used to:

a) Style web pages
b) Handle long-running tasks efficiently
c) Create layouts
d) Write CSS

Wait for 20 seconds...