Await for calling async functions in Swift - Mini Project: Build & Apply

Await for calling async functions

📖 Scenario: You are building a simple Swift program that fetches user data asynchronously, simulating a network call.

🎯 Goal: Learn how to call an async function and use await to get its result properly.

📋 What You'll Learn

Create an async function called fetchUserName() that returns a String

Create a variable called userName to store the result of calling fetchUserName()

Use await keyword to wait for the async function result

Print the userName variable

💡 Why This Matters

🌍 Real World

Async functions are used to fetch data from the internet or perform tasks that take time without freezing the app.

💼 Career

Understanding async/await is essential for modern Swift development, especially for apps that communicate with servers or do background work.

1

Create the async function

Write an async function called fetchUserName() that returns a String "Alice" after a short delay using Task.sleep.

Swift

# Your code here

Need a hint?

Use async keyword in the function signature and Task.sleep(nanoseconds:) to simulate delay.

2

Create a variable to hold the user name

Create a variable called userName of type String and initialize it with an empty string "".

Swift

import Foundation

func fetchUserName() async -> String {
    try? await Task.sleep(nanoseconds: 500_000_000) // 0.5 seconds delay
    return "Alice"
}

// Your code here

Need a hint?

Declare userName as a String variable and set it to an empty string.

3

Call the async function with await

Inside an async context, assign the result of calling fetchUserName() using await to the variable userName.

Swift

import Foundation

func fetchUserName() async -> String {
    try? await Task.sleep(nanoseconds: 500_000_000) // 0.5 seconds delay
    return "Alice"
}

var userName: String = ""

Task {
    // Your code here
}

Need a hint?

Use await before calling fetchUserName() inside the Task closure.

4

Print the user name

Inside the same async Task block, print the value of userName using print(userName).

Swift

import Foundation

func fetchUserName() async -> String {
    try? await Task.sleep(nanoseconds: 500_000_000) // 0.5 seconds delay
    return "Alice"
}

var userName: String = ""

Task {
    userName = await fetchUserName()
    // Your code here
}

Need a hint?

Use print(userName) inside the Task block to show the result.