Task for launching concurrent work in Swift - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a Task in Swift concurrency?

A Task represents a unit of asynchronous work that runs concurrently. It allows you to start work that can run independently from the current code flow.

beginner

How do you create a new concurrent task in Swift?

You create a new task by calling Task { ... } and placing asynchronous code inside the closure. This runs the code concurrently.

intermediate

What is the difference between Task and async/await?

async/await lets you write asynchronous code that waits for results, while Task launches work concurrently without blocking the current thread.

intermediate

How can you cancel a running Task?

You can call task.cancel() on the Task instance. Inside the task, you should check for cancellation using Task.isCancelled to stop work cooperatively.

beginner

What happens if you call Task { ... } inside a synchronous function?

The task starts running concurrently in the background immediately, allowing the synchronous function to continue without waiting for the task to finish.

Which Swift code launches a new concurrent task?

A Task { await fetchData() }

B fetchData()

C async fetchData()

D DispatchQueue.main.async { fetchData() }

Using Task { ... } launches a new concurrent task. Option D uses GCD, which is different from Swift concurrency tasks.

How do you check if a task has been cancelled inside its code?

A if task.isCancelled { ... }

B if Task.isCancelled { ... }

C if cancelled { ... }

D if Task.cancelled { ... }

Task.isCancelled is a static property to check cancellation inside the task.

What does Task { ... } return?

A An async function

B Void

C A DispatchQueue

D A Task instance representing the concurrent work

Task { ... } returns a Task instance that you can use to manage the concurrent work.

Which statement is true about Task in Swift concurrency?

A It runs code concurrently without blocking the current thread

B It blocks the current thread until the task finishes

C It only runs on the main thread

D It is used to create synchronous functions

Task runs code concurrently, allowing the current thread to continue.

How can you cancel a running Task?

A Set a flag variable to false

B Call <code>stop()</code> on the Task instance

C Call <code>cancel()</code> on the Task instance

D You cannot cancel a Task once started

You cancel a task by calling its cancel() method.

Explain how to launch concurrent work using Task in Swift and how cancellation works.

Think about starting work that runs alongside your current code and how you can stop it if needed.

Describe the difference between using async/await and launching a Task in Swift concurrency.

Consider when you want to wait for a result versus when you want to start work and continue immediately.