All Questions

Promises & Async/Await Interview Questions

MCQ Question 1 of 10

Question 1: Promise States

Which of the following is NOT a state of a JavaScript Promise?

PendingFulfilledRejectedRunning

Question 2: Creating a Promise

How do you create a new Promise?

let p = new Promise();let p = Promise(resolve, reject);let p = new Promise((resolve, reject) => {});let p = Promise();

Question 3: then() Method

What is the purpose of .then() in a Promise?

To reject the PromiseTo execute code when the Promise is fulfilledTo pause the PromiseTo create a new Promise

Question 4: catch() Method

What does .catch() do in a Promise chain?

Handles resolved valuesHandles rejected valuesStops the PromiseConverts a value to a Promise

Question 5: Async Function Return

What does an async function always return?

UndefinedA PromiseA valueA callback

Question 6: Await Keyword

What does the await keyword do?

Pauses the execution of the async function until the Promise resolvesRejects a PromiseConverts a function into a PromiseRuns code asynchronously outside the function

Question 7: Handling Errors with Async/Await

How do you properly catch errors in async/await?

Using try...catch blockUsing .then()Using .finally()Errors cannot be caught

Question 8: Promise.all()

What does Promise.all([p1, p2, p3]) do?

Resolves when any one Promise resolvesResolves when all Promises resolve or rejects if any rejectRejects all PromisesConverts all Promises to values immediately

Question 9: Multiple await Statements

How does execution behave with multiple await statements?

All await statements run in parallelEach await pauses execution sequentiallyAwait statements are ignoredExecution halts entirely

Question 10: Converting Promise to Async/Await

Which of the following is equivalent to:

fetchData().then(data => console.log(data)).catch(err => console.log(err));

let data = await fetchData(); console.log(data);try { let data = await fetchData(); console.log(data); } catch(err) { console.log(err); }await fetchData().then(console.log).catch(console.log);fetchData();