AngularJS - load google map script async in directive for multiple maps

Question

I am currently trying to load multiple google maps on a single page. I don't want to include google map API script into the HTML code as I don't want the script to be loaded unless the maps are in the current page. I want my maps to be called inside a single directive that will also perform the google map API script lazy loading.

So I searched around and found a solution that I tweaked a bit, but my problem is that it will only load one map but not the others.

My HTML looks like this:

<div id="mapParis" class="google-map" lat="48.833" long="2.333"></div>
<div id="mapWashington" class="google-map" lat="38.917" long="-77.000"></div>
<div id="mapTokyo" class="google-map" lat="35.667" long="139.750"></div>

And the directive:

// Google Map
app.directive('googleMap', ['$window', '$q', function( $window, $q ) {
    function loadScript() {
        console.log('loadScript');

        // use global document since Angular's $document is weak
        var s = document.createElement('script');
        s.src = '//maps.googleapis.com/maps/api/js?sensor=false&language=en&callback=initMap';
        document.body.appendChild(s);
    }

    // Lazy loading of the script
    function lazyLoadApi(key) {
        console.log('lazyLoadApi');

        var deferred = $q.defer();

        $window.initMap = function () {
            deferred.resolve();
        };

        if ( $window.attachEvent ) {  
            $window.attachEvent('onload', loadScript); 
        } else {
            $window.addEventListener('load', loadScript, false);
        }

        return deferred.promise;
    }

    return {
        restrict: 'C', // restrict by class name
        scope: {
            mapId: '@id', // map ID
            lat: '@',     // latitude
            long: '@'     // longitude
        },
        link: function($scope, elem, attrs) {
            // Check if latitude and longitude are specified
            if ( angular.isDefined($scope.lat) && angular.isDefined($scope.long) ) {
                console.log('-----');

                // Initialize the map
                $scope.initialize = function() {
                    console.log($scope.mapId);

                    $scope.location = new google.maps.LatLng($scope.lat, $scope.long);

                    $scope.mapOptions = {
                        zoom: 6,
                        center: $scope.location
                    };

                    $scope.map = new google.maps.Map(document.getElementById($scope.mapId), $scope.mapOptions);

                    new google.maps.Marker({
                        position: $scope.location,
                        map: $scope.map,
                    });
                }

                // Check if google map API is ready to run
                if ( $window.google && $window.google.maps ) {
                    console.log('gmaps already loaded');

                    // Google map already loaded
                    $scope.initialize();
                } else {
                    lazyLoadApi().then(function () {
                        // Promised resolved
                        console.log('promise resolved');

                        if ( $window.google && $window.google.maps ) {
                            // Google map loaded
                            console.log('gmaps loaded');

                            $scope.initialize();
                        } else {
                            // Google map NOT loaded
                            console.log('gmaps not loaded');
                        }
                    }, function () {
                        // Promise rejected
                        console.log('promise rejected');
                    });
                }
            }
        }
    };

Here is a jsFiddle with 3 maps, you will see that only the last one is loaded:
http://jsfiddle.net/5Pk8f/1/

I guess that I am doing something wrong with my scope or the way the promise is handled, but I am quite out of ideas for now...

Thanks! (and sorry for my not that good english)

Update (after answer)

As an update, here the the full solution I came up with:
http://plnkr.co/edit/1NpquJ?p=preview (@maurycy plunker)

Google map service

// Lazy loading of Google Map API
app.service('loadGoogleMapAPI', ['$window', '$q', 
    function ( $window, $q ) {

        var deferred = $q.defer();

        // Load Google map API script
        function loadScript() {  
            // Use global document since Angular's $document is weak
            var script = document.createElement('script');
            script.src = '//maps.googleapis.com/maps/api/js?sensor=false&language=en&callback=initMap';

            document.body.appendChild(script);
        }

        // Script loaded callback, send resolve
        $window.initMap = function () {
            deferred.resolve();
        }

        loadScript();

        return deferred.promise;
    }]);

Google map directive

// Google Map
app.directive('googleMap', ['$rootScope', 'loadGoogleMapAPI', 
    function( $rootScope, loadGoogleMapAPI ) {  

        return {
            restrict: 'C', // restrict by class name
            scope: {
                mapId: '@id', // map ID
                lat: '@',     // latitude
                long: '@'     // longitude
            },
            link: function( $scope, elem, attrs ) {

                // Check if latitude and longitude are specified
                if ( angular.isDefined($scope.lat) && angular.isDefined($scope.long) ) {

                    // Initialize the map
                    $scope.initialize = function() {                                        
                        $scope.location = new google.maps.LatLng($scope.lat, $scope.long);

                        $scope.mapOptions = {
                            zoom: 12,
                            center: $scope.location
                        };

                        $scope.map = new google.maps.Map(document.getElementById($scope.mapId), $scope.mapOptions);

                        new google.maps.Marker({
                            position: $scope.location,
                            map: $scope.map,
                        });
                    }

                    // Loads google map script
                    loadGoogleMapAPI.then(function () {
                        // Promised resolved
                        $scope.initialize();
                    }, function () {
                        // Promise rejected
                    });
                }
            }
        };
    }]);

HTML use sample

<div id="mapParis" class="google-map" lat="48.833" long="2.333"></div>
<div id="mapWashington" class="google-map" lat="38.917" long="-77.000"></div>
<div id="mapTokyo" class="google-map" lat="35.667" long="139.750"></div>

Thanks again to maurycy

Community · Accepted Answer · 2020-06-20 09:12:55Z

19

you have a problem here with promises and initialisation, i've made it cleaner for you

Apparently the jsfiddle has been removed so here is working plunker: http://plnkr.co/edit/1NpquJ?p=preview

js

here is a service for lazy load gmaps

app.service('lazyLoadApi', function lazyLoadApi($window, $q) {
  function loadScript() {
    console.log('loadScript')
    // use global document since Angular's $document is weak
    var s = document.createElement('script')
    s.src = '//maps.googleapis.com/maps/api/js?sensor=false&language=en&callback=initMap'
    document.body.appendChild(s)
  }
  var deferred = $q.defer()

  $window.initMap = function () {
    deferred.resolve()
  }

  if ($window.attachEvent) {
    $window.attachEvent('onload', loadScript)
  } else {
    $window.addEventListener('load', loadScript, false)
  }

  return deferred.promise
});

then the directive does what it should do, work only with map, don't load js files on any other logic

edited Jun 20, 2020 at 9:12

CommunityBot

11 silver badge

answered Jun 16, 2014 at 15:17

maurycy

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7 Comments

Niflhel Over a year ago

Thank you, it works perfectly. I am just wondering why it was not working as I did in my previous fiddle, in term of logic (it would help me having a better understanding of Angular).

maurycy Over a year ago

If you run your plunker you would see in console log that all 3 directives are initialised but only one promise (last one) was resolved and run the $scope.initialize()

InfoStatus Over a year ago

the fiddle is not working in any of the examples. Could you guys provide a full example

Aakash Over a year ago

$window.initMap function doesn't recognize deferred because it is not in its scope

alphapilgrim Over a year ago

Please update fiddle would like to see it in action, link is broken.

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