googleMapsLoader.js

angular.module('gps-test').factory('googleMapsLoader',
function($window, $q, $timeout) {
    "use strict"
    
    var loaded = false,
        listeners = [];
    
    function load_script(params, api_base_url) {
        
        var url = api_base_url || 'https://maps.googleapis.com/maps/api/js?',
            params_ext = angular.extend({sensor:false}, params);
        
        params_ext["callback"] = "googleMapsLoader_initialize";
        
        var params_str = [];
        angular.forEach(params_ext, function(val, key) {
            params_str.push(key+"="+String(val));
        });
        
        var s = $window.document.createElement('script');
        
        s.src = url + (params_str.join("&"));
        
        $window.document.head.appendChild(s);
    }
    
    function lazyLoadApi(params, api_base_url) {
        var deferred = $q.defer();

        if(!loaded) {// Not loaded yet
            if(listeners.length == 0) { //Load not initiated
                
                $window.googleMapsLoader_initialize = function () {
                    //Resolve all promises
                    angular.forEach(listeners, function(deferred) {
                        deferred.resolve($window.google.maps);
                    });
                    
                    loaded = true;
                    
                    //Memory clean
                    listeners = undefined;
                    delete $window["googleMapsLoader_initialize"];
                };
                
                $timeout(function(){
                    load_script(params, api_base_url);
                }, 0, false);
            }
            
            //Register promise
            listeners.push(deferred);
            
        } else { //Already loaded
            deferred.resolve($window.google.maps);
        }

        return deferred.promise;
    }

    var googleMapsLoader = {
        get: function(params, api_base_url) {
            return lazyLoadApi(params, api_base_url);
        }
    };

    return googleMapsLoader;
});

Usage

googleMapsLoader.get().then(function(googleMaps){
    console.log("Google Maps Loaded: ", googleMaps);
});

thank you:)

Thank you man!