Simple Readable Stream Example

alphabet-stream.js

const { Readable } = require('stream')

const charArray = 'abcdefghijklmnopqrstuvwxyz'.split('')

class AlphabetStream extends Readable {

  constructor () {
    super()
    this.position = 0
  }

  _read () {
    const index = this.position++
    if (index > charArray.length) this.push(null) // end
    else this.push(charArray[index]) // data
  }
}

new AlphabetStream()
  .on('data', char => console.log(`${char}`))
  // a
  // b
  // ...