iterate-evented-stream v0.1.9

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