Socket.io with AngularJS

chatControllerExample.coffee

'use strict';

angular.module('chatApp')
  .controller 'ChatCtrl', ($scope, Socket)->
    socket = Socket($scope)

    socket.emit 'subscribe', {}
    $scope.messages = [ ]

    socket.on 'message_history', (messages)->
      $scope.messages = messages

    socket.on 'user_list', (users)->
      $scope.users = users

    socket.on 'message_created', (msg)->
      $scope.messages.push msg

    socket.on 'message_deleted', (msg)->
      removeFromArray($scope.messages, msg)

    $scope.deleteMessage = (msg)->
      socket.emit 'delete_message', {id: msg._id}

    $scope.submitMessage = (form)->
      if form.$valid
        socket.emit 'create_message', {text: $scope.currentMessage}
        $scope.currentMessage = ""

loginControllerExample.coffee

"use strict"
angular.module("chatApp").controller "LoginCtrl", ($scope, Auth, $location, Socket) ->
  $scope.user = {}
  $scope.errors = {}
  $scope.login = (user) ->
    Auth.login(
      nickname: user.nickname
      password: user.password
    ).then ()->
      # Logged in, redirect to home
      Socket.reconnect()
      $location.path "/"
    .catch (err)->
      err = err.data;
      $scope.errors.other = err.message;

socket.coffee

"use strict"
angular.module("chatApp").factory "Socket", ($rootScope) ->
  # io is a global object available if you included socket.io script:
  socket = io.connect()
  ###
    $scope - scope of a controller
    global - boolean indicating whether a change applies only
             to a local scope or to a $rootScope
             (in case perfomansc is an issues)
  ###
  resultObject = ($scope, global = true)->
    scopeOfChange = if global then $rootScope else $scope
    # create an array of listeners if there is none (notice '?' operator):
    $scope._listeners?= []
    # if controller's scope is destroyed then $destroy event is fired
    # on this event we should get rid of all listeners on this scope:
    $scope.$on '$destroy', (event)->
      for lis in $scope._listeners
        socket.removeListener(lis.eventName, lis.ngCallback)
      $scope._listeners.length=0

    # return familiar to us socket.io object that can listen to and emit events:
    return  {
      on: (eventName, callback) ->
        ngCallback = ()->
          args = arguments          
          # trigger angular $digest cycle on selected scope:
          scopeOfChange.$apply ->
            callback.apply socket, args # apply function to original object
        # save listener to a list on current scope so we can remove it later:
        $scope._listeners.push {
          eventName
          ngCallback
        }
        # pass our own callback that wraps the one passed by a user
        socket.on eventName, ngCallback

      emit: (eventName, data, callback) ->
        socket.emit eventName, data, ->
          args = arguments
          scopeOfChange.$apply ->
            callback.apply socket, args  if callback
    }
  # sometimes I find reconnect to be usefull:
  resultObject.reconnect = ()->
    socket.socket.disconnect()
    socket.socket.connect()
  return resultObject