channels.js

const Immutable = require('immutable')

const add = (channels, name) => {
  return channels.set(name, Immutable.List())
}

const addAction = (channels, name, action) => {
  return channels.set(name, channels.get(name).push(action))
}

const addListener = (channels, name, action) => {
  if (!channels.has(name)) {
    const newChannels = add(channels, name) 
    return addAction(newChannels, name, action)
  }
  return addAction(...args)
}

const doActions = (channels, name, data) => {
  if (channels.has(name)) {
    channels.get(name).forEach((action) => {
      action(data)
    })
  }
}

let channels = Immutable.Map()

module.exports = {
  subscribe: (name, action) => {
    channels = addListener(channels, name, action)
  },
  emit: (name, data) => {
    doActions(channels, name, data)
  }
}

event-emmiter.js

const channels = require('./channels')

const logger = console.log.bind(console)

channels.subscribe('channel1', logger)

channels.emit('channel1', 'hello world!')