AbortController for cancellation in React Native - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is AbortController used for in React Native?

AbortController helps you stop or cancel a running task, like a network request, before it finishes. It’s like pressing a stop button to save resources.

beginner

How do you create an AbortController instance?

You create it by calling new AbortController(). This gives you a controller with a signal property to pass to fetch or other cancellable tasks.

beginner

How do you cancel a fetch request using AbortController?

Call controller.abort(). This sends a signal to stop the fetch request immediately.

intermediate

What happens if you call abort() on an AbortController while a fetch is running?

The fetch promise rejects with an error named AbortError. You can catch this error to handle cancellation gracefully.

beginner

Why is it important to cancel network requests in mobile apps?

Cancelling saves battery, reduces data use, and prevents your app from doing unnecessary work when the user moves on or the screen changes.

How do you pass the AbortController signal to a fetch request?

A As the second argument in fetch options under the key 'signal'

B As the first argument to fetch

C By calling fetch.abort()

D By setting fetch.signal = controller

You pass the signal as an option: fetch(url, { signal: controller.signal })

What method do you call to cancel a fetch request?

A controller.abort()

B controller.cancel()

C fetch.cancel()

D fetch.abort()

AbortController uses the abort() method to cancel tasks.

What error name is thrown when a fetch is aborted?

A NetworkError

B FetchError

C CancelError

D AbortError

The error thrown is named AbortError.

Why should you cancel fetch requests in React Native apps?

A To speed up the app startup

B To save battery and data

C To avoid syntax errors

D To increase font size

Cancelling saves battery and data by stopping unnecessary work.

Which of these is NOT true about AbortController?

A It can cancel fetch requests

B It helps manage asynchronous tasks

C It can be reused after aborting

D It provides a signal property

Once aborted, an AbortController cannot be reused.

Explain how AbortController helps manage network requests in React Native.

Think about how you start and stop a task.

Describe why cancelling fetch requests is important in mobile app development.

Imagine your phone’s battery and data plan.