Await keyword behavior in Javascript - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the await keyword do in JavaScript?

It pauses the execution of an async function until the Promise after await settles (resolves or rejects), then resumes with the resolved value or throws the rejection.

beginner

Can await be used outside of an async function?

No, await can only be used inside async functions or in top-level modules that support top-level await.

intermediate

What happens if you await a non-Promise value?

The value is converted to a resolved Promise automatically, so await returns the value immediately without delay.

intermediate

How does await affect the event loop?

await pauses the async function but allows other code and events to run in the event loop until the awaited Promise settles.

intermediate

What is the difference between await and .then()?

await makes asynchronous code look synchronous and pauses execution, while .then() registers callbacks without pausing execution.

Where can you use the await keyword in JavaScript?

A Only inside callback functions

B Inside async functions or top-level modules with top-level await

C Only inside regular functions

D Anywhere in the code

await works only inside async functions or in modules that support top-level await.

What does await do when given a non-Promise value?

A Throws an error

B Waits indefinitely

C Returns the value immediately as if it was a resolved Promise

D Converts it to a rejected Promise

await treats non-Promise values as resolved Promises and returns them immediately.

What happens to the rest of the program when an async function hits await?

A Only the async function pauses; other code continues running

B The whole program stops

C The browser reloads

D The event loop freezes

Only the async function pauses at await, allowing other code and events to run.

Which of these is a key difference between await and .then()?

A <code>await</code> pauses execution; <code>.then()</code> does not

B <code>.then()</code> pauses execution; <code>await</code> does not

C Both pause execution

D Neither pause execution

await pauses the async function, making code look synchronous; .then() uses callbacks without pausing.

If a Promise rejects, what happens when you use await on it?

A The rejection is ignored

B The Promise resolves instead

C The program crashes immediately

D The async function throws an error at the <code>await</code> line

When a Promise rejects, await throws an error that can be caught with try/catch.

Explain how the await keyword changes the flow of an async function.

Think about how <code>await</code> makes asynchronous code easier to read.

Describe the difference between using await and .then() for handling Promises.

Consider how the code looks and behaves when using each.