index.js

var splice = require('remove-array-items')
var nanotiming = require('nanotiming')
var assert = require('assert')

module.exports = Nanobus

function Nanobus (name) {
  if (!(this instanceof Nanobus)) return new Nanobus(name)

  this._name = name || 'nanobus'
  this._starListeners = []
  this._listeners = {}
}

Nanobus.prototype.emit = function (eventName) {
  assert.ok(typeof eventName === 'string' || typeof eventName === 'symbol', 'nanobus.emit: eventName should be type string or symbol')

  var data = []
  for (var i = 1, len = arguments.length; i < len; i++) {
    data.push(arguments[i])
  }

  var emitTiming = nanotiming(this._name + "('" + eventName.toString() + "')")
  var listeners = this._listeners[eventName]
  if (listeners && listeners.length > 0) {
    this._emit(this._listeners[eventName], data)
  }

  if (this._starListeners.length > 0) {
    this._emit(this._starListeners, eventName, data, emitTiming.uuid)
  }
  emitTiming()

  return this
}

Nanobus.prototype.on = Nanobus.prototype.addListener = function (eventName, listener) {
  assert.ok(typeof eventName === 'string' || typeof eventName === 'symbol', 'nanobus.on: eventName should be type string or symbol')
  assert.equal(typeof listener, 'function', 'nanobus.on: listener should be type function')

  if (eventName === '*') {
    this._starListeners.push(listener)
  } else {
    if (!this._listeners[eventName]) this._listeners[eventName] = []
    this._listeners[eventName].push(listener)
  }
  return this
}

Nanobus.prototype.prependListener = function (eventName, listener) {
  assert.ok(typeof eventName === 'string' || typeof eventName === 'symbol', 'nanobus.prependListener: eventName should be type string or symbol')
  assert.equal(typeof listener, 'function', 'nanobus.prependListener: listener should be type function')

  if (eventName === '*') {
    this._starListeners.unshift(listener)
  } else {
    if (!this._listeners[eventName]) this._listeners[eventName] = []
    this._listeners[eventName].unshift(listener)
  }
  return this
}

Nanobus.prototype.once = function (eventName, listener) {
  assert.ok(typeof eventName === 'string' || typeof eventName === 'symbol', 'nanobus.once: eventName should be type string or symbol')
  assert.equal(typeof listener, 'function', 'nanobus.once: listener should be type function')

  var self = this
  this.on(eventName, once)
  function once () {
    listener.apply(self, arguments)
    self.removeListener(eventName, once)
  }
  return this
}

Nanobus.prototype.prependOnceListener = function (eventName, listener) {
  assert.ok(typeof eventName === 'string' || typeof eventName === 'symbol', 'nanobus.prependOnceListener: eventName should be type string or symbol')
  assert.equal(typeof listener, 'function', 'nanobus.prependOnceListener: listener should be type function')

  var self = this
  this.prependListener(eventName, once)
  function once () {
    listener.apply(self, arguments)
    self.removeListener(eventName, once)
  }
  return this
}

Nanobus.prototype.removeListener = function (eventName, listener) {
  assert.ok(typeof eventName === 'string' || typeof eventName === 'symbol', 'nanobus.removeListener: eventName should be type string or symbol')
  assert.equal(typeof listener, 'function', 'nanobus.removeListener: listener should be type function')

  if (eventName === '*') {
    this._starListeners = this._starListeners.slice()
    return remove(this._starListeners, listener)
  } else {
    if (typeof this._listeners[eventName] !== 'undefined') {
      this._listeners[eventName] = this._listeners[eventName].slice()
    }

    return remove(this._listeners[eventName], listener)
  }

  function remove (arr, listener) {
    if (!arr) return
    var index = arr.indexOf(listener)
    if (index !== -1) {
      splice(arr, index, 1)
      return true
    }
  }
}

Nanobus.prototype.removeAllListeners = function (eventName) {
  if (eventName) {
    if (eventName === '*') {
      this._starListeners = []
    } else {
      this._listeners[eventName] = []
    }
  } else {
    this._starListeners = []
    this._listeners = {}
  }
  return this
}

Nanobus.prototype.listeners = function (eventName) {
  var listeners = eventName !== '*'
    ? this._listeners[eventName]
    : this._starListeners

  var ret = []
  if (listeners) {
    var ilength = listeners.length
    for (var i = 0; i < ilength; i++) ret.push(listeners[i])
  }
  return ret
}

Nanobus.prototype._emit = function (arr, eventName, data, uuid) {
  if (typeof arr === 'undefined') return
  if (arr.length === 0) return
  if (data === undefined) {
    data = eventName
    eventName = null
  }

  if (eventName) {
    if (uuid !== undefined) {
      data = [eventName].concat(data, uuid)
    } else {
      data = [eventName].concat(data)
    }
  }

  var length = arr.length
  for (var i = 0; i < length; i++) {
    var listener = arr[i]
    listener.apply(listener, data)
  }
}