Await keyword in iOS Swift - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the await keyword do in Swift?

The await keyword pauses the current function until an asynchronous task finishes, allowing other code to run meanwhile.

beginner

Can you use await outside an asynchronous function in Swift?

No, await can only be used inside functions marked with async.

intermediate

How does await improve app responsiveness?

await lets the app do other work while waiting for slow tasks, like network calls, so the app stays smooth and doesn’t freeze.

intermediate

What happens if you forget to use await when calling an async function?

The async function returns a task immediately without waiting for the result, which can cause bugs if you expect the result right away.

beginner

Example: What does this code do?
<pre>func fetchData() async {
  let data = await download()
  print(data)
}</pre>

This function waits for download() to finish before printing the data. The await pauses fetchData() until download() completes.

Where can you use the await keyword in Swift?

A Only inside functions marked with <code>async</code>

B Inside any function

C Only in the main thread

D Only in classes

await must be inside async functions to pause and wait for asynchronous tasks.

What does await do when calling an async function?

A Pauses execution until the async function finishes

B Ignores the function result

C Runs the function synchronously

D Runs the function twice

await pauses the current function until the async function completes and returns a result.

What happens if you call an async function without await?

A You get a compile error

B You get a task object immediately without waiting

C The function runs synchronously

D The app crashes

Calling an async function without await returns a task immediately, not the final result.

Why is using await good for app performance?

A It blocks the main thread

B It makes code run faster synchronously

C It lets other code run while waiting

D It disables multitasking

await allows the app to stay responsive by letting other tasks run while waiting for slow operations.

Which keyword must a function have to use await inside it?

A defer

B sync

C await

D async

Only functions marked with async can use await to wait for asynchronous tasks.

Explain in your own words how the await keyword works in Swift and why it is useful.

Think about how waiting for slow tasks can freeze an app and how <code>await</code> helps avoid that.

Describe a simple example where you would use await in a Swift app.

Imagine fetching data from the internet and needing to wait for it before showing it.