(with off()) createEventBus.js

  const createEventBus = () => {
    const subscribers = {}
    let counter = 0

    const on = (name, cb) => {
      if (!subscribers[name]) subscribers[name] = {}
      subscribers[name][++counter] = cb
      return btoa(name + '.' + counter)
    }

    const off = (id) => {
      const [name, prop] = atob(id).split('.')
      subscribers[name] && delete subscribers[name][prop]
    }

    const emit = (name, ...args) => {
      if (subscribers[name])
        Object.values(subscribers[name]).forEach((cb) => cb(...args))
    }

    return { on, off, emit }
  }

createEventBus.js

const createEventBus = () => {
  const subscribers = {}

  const on = (name, cb) => {
    subscribers[name]
      ? subscribers[name].push(cb)
      : (subscribers[name] = [cb])
  }

  const off = () => {}

  const emit = (name, ...args) => {
    if (subscribers[name]) subscribers[name].forEach((cb) => cb(...args))
  }

  return { on, off, emit }
}

events.js

const events = (() => {
  const subscribers = {}
  const on = (eventName, cb) => {
    subscribers[eventName]
      ? subscribers[eventName].push(cb)
      : (subscribers[eventName] = [cb])
  }
  const emit = (eventName, ...args) => {
    if (subscribers[eventName]) {
      subscribers[eventName].forEach(cb => cb(...args))
    }
  }
  return { on, emit }
})()