index.js

let createNanoEvents = () => ({
  events: {},
  emit (event, ...args) {
    for (let i of this.events[event] || []) {
      i(...args)
    }
  },
  on (event, cb) {
    ;(this.events[event] = this.events[event] || []).push(cb)
    return () => (this.events[event] = this.events[event].filter(i => i !== cb))
  }
})

module.exports = { createNanoEvents }