Allow multiple readers to iterate over a stream at the same time
Nobody has claimed this yet.
- Dominant language
- JavaScript
- Stars
- 122k
- Forks
- 37.3k
- Avg merge
- 4d 2h
- Merged PRs (30d)
- 283
Description
What is the problem this feature will solve?
When multiple callers use Readable[Symbol.asyncIterator], each caller receives a partial result.
import {Readable} from 'node:stream'
const stream = Readable.from(['a', 'b', 'c'])
const iterate = async (readerName) => {
for await (const chunk of stream) {
console.log(readerName, chunk)
}
}
await Promise.all([
iterate('one'),
iterate('two'),
])
one a
two b
one c
Some callers might expect that result. But others might expect the following result instead.
one a
two a
one b
two b
one c
two c
What is the feature you are proposing to solve the problem?
Adding an option to readable.iterator() to use readable.on('data') instead of readable.read(). This would enable the above behavior.
What alternatives have you considered?
Implementing this user-land.
See an example of it at https://github.com/sindresorhus/get-stream/pull/121
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start in lib/internal/streams/readable.js at Readable[Symbol.asyncIterator] and inspect how readable.iterator() currently consumes the stream. Compare the proposed data-event behavior with the supplied concurrent iteration example; done means an option is defined and multiple readers receive each chunk as documented.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- javascript, node.js
- Domain
- api, backend
- Issue type
- Feature
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 35/100