Await for calling async functions in Swift - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the await keyword do in Swift?

It pauses the current function until the asynchronous function finishes and returns its result.

beginner

How do you mark a Swift function as asynchronous?

By adding the async keyword after the function's parameter list and before the return type.

beginner

Why do you need to use await when calling an async function?

Because async functions run asynchronously and await tells Swift to wait for the result before continuing.

intermediate

Can you call an async function without await in Swift?

No, you must use await to call an async function unless you handle it differently with tasks or concurrency APIs.

intermediate

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

The code will not compile because Swift requires await to handle asynchronous calls properly.

Which keyword do you use to wait for an async function to finish in Swift?

A await

B async

C defer

D sync

The await keyword pauses execution until the async function completes.

How do you declare a function that can be awaited in Swift?

A func myFunc() async -> String

B func myFunc() await -> String

C async func myFunc() -> String

D func async myFunc() -> String

The async keyword goes after the parameter list and before the return type.

What must you add before calling an async function inside another async function?

A try

B async

C await

D defer

You use await to wait for the async function's result.

If you call an async function without await, what happens?

A Runs asynchronously without waiting

B Compilation error

C Runs synchronously

D Returns nil

Swift requires await to call async functions; otherwise, it won't compile.

Which of these is a correct way to call an async function named fetchData() inside an async function?

A async let data = fetchData()

B let data = fetchData()

C await let data = fetchData()

D let data = await fetchData()

You use await before the function call to wait for its result.

Explain how and why you use await when calling async functions in Swift.

Think about waiting for a friend to finish before continuing your task.

Describe the syntax for declaring and calling an async function in Swift.

Remember the order: declare async, call with await.