pubSub.js

//`first` reads the data from the service
Controller first (myService) ->
    this.firstValue = myService.get().firstValue //using a getter so there's no direct reference
    
    myService.onChange(function(newData) {
        this.firstValue = newData.firstValue
    })


//`second` sets the data inside the service
Controller second (myService) ->
    myService.set('firstValue', this.secondValue);


// 'myService' can handle the event subscription
Service myService ($http, $rootScope) ->
    function get ->
        $http.get().then(fireEvent)
    
    //  using the $rootScope (if we wont have many of these istances)
    function onChange(cb) ->
        $rootScope.$on('myService:change', cb)
    
    function fireEvent (data)->
        $rootScope.$emit('myService:change', data)
    
    // or we can use a custom pub/sub class that doesnt touch the rootScope