Iterate Evented Stream

Create an AsyncIterable from an evented stream.

Usage Examples

All code snippets below work in an async context.

Custom EventEmitter

In order for an EventEmitter to be a valid EventTarget,

• It must listen to 3 required events:

  • ('data', string)
  • ('error', Error)
  • ('close')

• It must provide 2 required methods for each event:

  • addListener
  • removeListener

• Iteration stops when the EventEmitter emits 'close' or 'error'

  • If it emits 'close', iteration is considered completed.
  • If it emits 'error', iteration throws the emitted error.

const EventEmitter = require('events')
const iterate = require('iterate-evented-stream')
const emitter = new EventEmitter()

setTimeout(() => emitter.emit('data', '100 ms'), 100)
setTimeout(() => emitter.emit('data', '200 ms'), 200)
setTimeout(() => emitter.emit('data', '300 ms'), 300)
setTimeout(() => emitter.emit('data', '400 ms'), 400)
setTimeout(() => emitter.emit('close'), 500)

for await (const chunk of iterate(emitter)) {
  console.log(chunk)
}

Expected Result:

100 ms
200 ms
300 ms
400 ms

Child Process

NOTE: Replace foo, bar and baz below with commands that exist.

const { spawn } = require('child_process')
const combine = require('combine-evented-stream')
const iterate = require('iterate-evented-stream')

const cps = [
  'foo',
  'bar',
  'baz'
].map(program => spawn(program))

const stream = combine(cps)

for await (const { stream, chunk } of iterate(stream)) {
  console.log({
    pid: stream.pid,
    data: chunk
  })
}

console.log('done.')

License

MIT © Hoàng Văn Khải