All 10 Async Iterators & Streams questions
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How do you loop over an async iterable? How do you write an async generator function? What is the ReadableStream API used for? What does return() do on an async iterator? How do you convert a Node.js Readable stream into an async iterable? How do you run multiple async iterators concurrently and merge their results? What's the difference between piping streams with pipeThrough() and pipeTo()? Why might Promise.all() be the wrong tool when consuming many async iterators? How do you add a timeout to an async iterator's next() call?
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JavaScript › Async Iterators & Streams

What is an async iterator?

Beginner

Answer

An async iterator is an object with a next() method that returns a Promise resolving to {value, done}, letting you iterate over values that arrive asynchronously over time, like chunks from a network stream.
const iterator = someAsyncIterable[Symbol.asyncIterator]();
const { value, done } = await iterator.next();
Real-world example Reading lines from a large file or paginated API results one chunk at a time.

Common follow-ups: How is Symbol.asyncIterator different from Symbol.iterator?

Iterators & Generators
All 10 Async Iterators & Streams questions