Async functions declaration in Swift - Cheat Sheet & Quick Revision

Recall & Review

beginner

What keyword do you use in Swift to declare an asynchronous function?

You use the async keyword after the function's parameter list to declare it as asynchronous.

intermediate

How do you mark a Swift function that can throw errors and is asynchronous?

You place async before throws in the function declaration, like func fetchData() async throws.

beginner

What is the purpose of declaring a function as async in Swift?

Declaring a function as async means it can perform work that might take time without blocking the program, allowing other code to run while waiting.

beginner

Show the syntax of a simple async function in Swift that returns an integer.

Example:<br>

func getNumber() async -> Int {
    return 42
}

intermediate

Can an async function in Swift be called like a normal function? Why or why not?

No, async functions must be called with await because they might pause execution until the result is ready.

Which keyword is used to declare an asynchronous function in Swift?

A async

B await

C defer

D throws

The async keyword declares a function as asynchronous.

How do you call an async function in Swift?

A Just call it like a normal function

B Use the <code>await</code> keyword before the call

C Use the <code>async</code> keyword before the call

D Use the <code>try</code> keyword only

You must use await to call an async function because it might pause execution.

What does the async keyword indicate about a Swift function?

A It can pause and resume later without blocking

B It throws an error

C It runs instantly without delay

D It is a private function

async means the function can pause and resume, allowing other code to run meanwhile.

Which of these is a correct async function declaration in Swift?

A async func loadData() throws -> String

B func loadData() throws async -> String

C func loadData() async throws -> String

D func async loadData() throws -> String

The correct order is async before throws in the declaration.

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

A defer

B async

C try

D await

You use await to wait for the async function to finish.

Explain how to declare an async function in Swift and why you would use it.

Think about how async helps with waiting for tasks without stopping the whole program.

Describe the difference between calling a normal function and an async function in Swift.

Focus on what you add before calling an async function and why.