What are the pitfalls of using for await...of with an async generator that makes network calls? How do you handle errors and cancellation?

Q: What are the pitfalls of using for await...of with an async generator that makes network calls? How do you handle errors and cancellation?

const ac = new AbortController(); try { for await (const page of fetchPages(url, ac.signal)) { if (stopCondition) ac.abort(); } } catch (err) { console.error('Fetch failed', err); }

Difficulty: 8/10

async generators, error handling, cancellation

Pitfalls include unhandled rejections and lack of cancellation. Handle errors with try/catch inside or around the loop. Use AbortController to cancel ongoing requests.

Error handling and cancellation

Scenario Questions

0-2 years experience

1You need to fetch a list of user profiles from an API using an async generator and process each with a for await...of loop. How would you write that loop to ensure a failed request doesn't stop processing the rest?
2If the network call inside the generator throws a timeout error, what will happen to the for await...of iteration, and how can you catch it locally?

2-5 years experience

Follow-up Questions

Can you sketch a minimal code example that catches errors inside the loop?
How would you pass a cancellation token into the async generator?
What happens to the event loop if a promise in the generator is never settled?