Example proofing the sequential processing of es map

mapstream.js

const es = require('event-stream');
const R = require('ramda');

function getRandomInt(min, max) {
  var min = Math.ceil(min);
  var max = Math.floor(max);
  return Math.floor(Math.random() * (max - min)) + min;
}

const readable = es.readArray(R.map(R.toString, R.range(1, 5000)));

const map = es.map((data, cb) => {
  const ms = getRandomInt(1000, 5000);

  setTimeout(() => {
    console.log('>>>', data, ms)
    cb(null, data + '\n');
  }, ms);
});

readable.pipe(map).pipe(process.stdout);