AngularJS: lazy loading controllers and content

Problem

In this simplified scenario, I have two files: index.htm, lazy.htm.

index.htm:

var myApp = angular.module('myApp', []);
myApp.controller('embed',function($scope){
    $scope.embed = 'Embedded Controller';
});                  
<div ng-controller="embed">{{embed}}</div>    
<div ng-include="'lazy.htm'"></div>

lazy.htm

myApp.controller('lazy',function($scope){
    $scope.lazy = 'Lazy Controller';
});
<div ng-controller="lazy">
    {{lazy}}
</div>

The result is an error: "Argument 'lazy' is not a function, got undefined"

Using a function instead

lazy.htm

function lazy($scope) {
    $scope.lazy = 'Lazy Controller';
}
<div ng-controller="lazy">
    {{lazy}}
</div>

This works until version 1.3 beta 14. In beta 15 was removed the global controller functions: https://github.com/angular/angular.js/issues/8296

So now, what is the better way to get angularized contents of lazy.htm dynamically?

UPDATE:

In this article (http://ify.io/lazy-loading-in-angularjs) I found another possible solution. The $controllerProvider allow us to register new controllers after angular bootstrap. Works like a charm. Tested in v1.3.0-beta.18

index.htm:

var myApp = angular.module('myApp', [])
.controller('embed',function($scope){
    $scope.embed = 'Embedded Controller';
})
.config(function($controllerProvider) {
    myApp.cp = $controllerProvider;
});

<div ng-controller="embed">{{embed}}</div>    
<div ng-include="'lazy.htm'"></div>

lazy.htm

myApp.cp.register('lazy',function($scope){
    $scope.lazy = 'Lazy Controller';
});
<div ng-controller="lazy">
    {{lazy}}
</div>

UPDATE 2:

Two other alternatives that works are:

lazy.htm

_app = $('[ng-app]').scope();    
_app.lazy = function($scope) {
    $scope.lazy = 'Lazy Controller';
};

OR

var $rootScope = $('[ng-app]').injector().get('$rootScope');        
$rootScope.lazy = function($scope) {
    $scope.lazy = 'Lazy Controller';
}; 

But I believe these last two examples should not be used in production.

Problem courtesy of: Rodolfo Jorge Nemer Nogueira

Solution

You can also use the jquery with the resolve the $routeProvider

app.js

/* Module Creation */
var app = angular.module ('app', ['ngRoute']);

app.config(['$routeProvider', '$controllerProvider', function($routeProvider, $controllerProvider){

/*Creating a more synthesized form of service of $ controllerProvider.register*/
app.registerCtrl = $controllerProvider.register;

function loadScript(path) {
  var result = $.Deferred(),
  script = document.createElement("script");
  script.async = "async";
  script.type = "text/javascript";
  script.src = path;
  script.onload = script.onreadystatechange = function (_, isAbort) {
      if (!script.readyState || /loaded|complete/.test(script.readyState)) {
         if (isAbort)
             result.reject();
         else
            result.resolve();
    }
  };
  script.onerror = function () { result.reject(); };
  document.querySelector("head").appendChild(script);
  return result.promise();
}

function loader(arrayName){

    return {
      load: function($q){
                var deferred = $q.defer(),
                map = arrayName.map(function(name) {
                    return loadScript('js/controllers/'+name+".js");
                });

                $q.all(map).then(function(r){
                    deferred.resolve();
                });

                return deferred.promise;
        }
    };
}

$routeProvider  
    .when('/', {
        templateUrl: 'views/foo.html',
        resolve: loader(['foo'])
    })
    .when('/bar',{
        templateUrl: 'views/bar.html',
        controller: 'BarCtrl',
        resolve: loader(['bar'])
    })
    .otherwise({
        redirectTo: document.location.pathname
    });
}]);

/views/foo.html

<section ng-controller='FooCtrl'>
    {{text}}
</section>

js/controllers/foo.js

/*Here we use the synthesized version of $controllerProvider.register 
to register the controller in view*/
app.registerCtrl('FooCtrl',function($scope){
    $scope.text = 'Test';
});

/views/bar.html

<section>
    {{text2}}
</section>

js/controllers/bar.js

app.registerCtrl('BarCtrl',function($scope){
    $scope.text2 = 'Test';
});
Solution courtesy of: André Betiolo

Discussion

I am sending you sample code. It is working fine for me. So please check this:

var myapp = angular.module('myapp', ['ngRoute']);

/* Module Creation */
var app = angular.module('app', ['ngRoute']);

app.config(['$routeProvider', '$controllerProvider', function ($routeProvider, $controllerProvider) {

app.register = {
    controller: $controllerProvider.register,
    //directive: $compileProvider.directive,
    //filter: $filterProvider.register,
    //factory: $provide.factory,
    //service: $provide.service
};


//    so I keep a reference from when I ran my module config
function registerController(moduleName, controllerName) {
    // Here I cannot get the controller function directly so I
    // need to loop through the module's _invokeQueue to get it
    var queue = angular.module(moduleName)._invokeQueue;
    for (var i = 0; i < queue.length; i++) {
        var call = queue[i];
        if (call[0] == "$controllerProvider" &&
           call[1] == "register" &&
           call[2][0] == controllerName) {
            app.register.controller(controllerName, call[2][1]);
        }
    }
}


var tt = {
    loadScript:
function (path) {
    var result = $.Deferred(),
    script = document.createElement("script");
    script.async = "async";
    script.type = "text/javascript";
    script.src = path;
    script.onload = script.onreadystatechange = function (_, isAbort) {
        if (!script.readyState || /loaded|complete/.test(script.readyState)) {
            if (isAbort)
                result.reject();
            else {
                result.resolve();
            }
        }
    };
    script.onerror = function () { result.reject(); };
    document.querySelector(".shubham").appendChild(script);
    return result.promise();
}
}

function stripScripts(s) {
    var div = document.querySelector(".shubham");
    div.innerHTML = s;
    var scripts = div.getElementsByTagName('script');
    var i = scripts.length;
    while (i--) {
        scripts[i].parentNode.removeChild(scripts[i]);
    }
    return div.innerHTML;
}


function loader(arrayName) {
    return {
        load: function ($q) {
            stripScripts(''); // This Function Remove javascript from Local
            var deferred = $q.defer(),
            map = arrayName.map(function (obj) {
                return tt.loadScript(obj.path)
                .then(function () {
                    registerController(obj.module, obj.controller);
                })
            });

            $q.all(map).then(function (r) {
                deferred.resolve();
            });
            return deferred.promise;
        }
    };
};



$routeProvider
    .when('/first', {
        templateUrl: '/Views/foo.html',
        resolve: loader([{ controller: 'FirstController', path: '/MyScripts/FirstController.js', module: 'app' },
            { controller: 'SecondController', path: '/MyScripts/SecondController.js', module: 'app' }])
    })

    .when('/second', {
        templateUrl: '/Views/bar.html',
        resolve: loader([{ controller: 'SecondController', path: '/MyScripts/SecondController.js', module: 'app' },
        { controller: 'A', path: '/MyScripts/anotherModuleController.js', module: 'myapp' }])
    })
    .otherwise({
        redirectTo: document.location.pathname
        });
}])

And in HTML Page:

<body ng-app="app">

<div class="container example">
    <!--ng-controller="testController"-->

    <h3>Hello</h3>

    <table>
        <tr>
            <td><a href="#/first">First Page </a></td>
            <td><a href="#/second">Second Page</a></td>
        </tr>
    </table>




        <div id="ng-view" class="wrapper_inside" ng-view>
        </div>
    <div class="shubham">
    </div>
</div>

Thank U

Discussion courtesy of: s_kumar

You also can use Directives to load your controller!

A example here:

https://gist.github.com/raphaelluchini/53d08ed1331e47aa6a87

Discussion courtesy of: raphaelluchini

The best way to do what you are asking is to instead use a directive and tie the controller and template together that way so its bound at the appropriate time. Currently, the binding it not happening in lazy.htm at the right time unless you declare a global function as you've shown in your second example.

Discussion courtesy of: Fourth

You can have pure AngularJS lazy loading.

Create "LazyService":

var ng = angular.module('app');

ng.factory('lazyService', [ '$http', function($http) {
    var jsPath = 'js/${ name }.js';
    var promisesCache = {};

    return {
        loadScript: function(name) {
            var path = jsPath.replace('${ name }', name);
            var promise = promisesCache[name];
            if (!promise) {
                promise = $http.get(path);
                promisesCache[name] = promise;

                return promise.then(function(result) {
                    eval(result.data);
                    console.info('Loaded: ' + path);
                });
            }

            return promise;
        }
    }
}]);

Then, define your config:

var ng = angular.module('app', [ 'ngRoute' ]);

ng.config([ '$routeProvider', '$controllerProvider', '$provide', function($routeProvider, $controllerProvider, $provide) {
    // Lazy loading
    ng.lazy = {
        controller: $controllerProvider.register,
        //directive: $compileProvider.directive,
        //filter: $filterProvider.register,
        factory: $provide.factory,
        service: $provide.service
    }

    $routeProvider
    .when('/', {
        templateUrl: 'view/home.html'
    })
    .when('/vendor', {
        templateUrl: 'view/vendor.html',
        resolve: {
            svc: [ 'lazyService', function(lazyService) {
                return lazyService.loadScript('services/vendor');
            }],
            ctrl: [ 'lazyService', function(lazyService) {
                return lazyService.loadScript('controllers/vendor');
            }]
        }
    });
. . .

On "js/services/vendor.js", create service as:

var ng = angular.module('app');
ng.lazy.service('vendorService', [ function() {
. . .

On "js/controllers/vendor.js", create controller as:

var ng = angular.module('app');
ng.lazy.controller('vendorController', [ function() {
. . .

The "resolve" property on when defines which promises should be resolved before route loads.

Discussion courtesy of: Skarllot

Ideally - Angular will force you to separate HTML and JS as in newer versions this may be enforced more often.

You may have to use requireJS http://solutionoptimist.com/2013/09/30/requirejs-angularjs-dependency-injection/

For the sake of trick can you try

ng-controller-controller="'lazy'"

or

In HTML

ng-controller-controller="myObject.controller"

Somewhere inject

$scope.myObject.controller = $controller('lazy', {$scope: $scope})
Discussion courtesy of: bhantol

Try this ARI plugin for Angular JS. It helps you to lazy load the controller scripts on demand.

Discussion courtesy of: Nirus

At first I utilized André Betiolo's answer. However, it does not always work becasue the ajax loading is non-blocking causing the view to sometimes request the controller prior to the script being loaded.

As a solution i forced the function not to return until all scripts successfully loaded. This is kind of hackish but makes sure the loads are successful prior to completing the resolve. It also allows for loading of multiple controllers.

app.js

var app = angular.module ('app', ['ngRoute']);

app.config(['$routeProvider', '$controllerProvider', function($routeProvider, $controllerProvider){

    /*Creating a more synthesized form of service of $ controllerProvider.register*/
    app.registerCtrl = $controllerProvider.register;

    //jquery to dynamically include controllers as needed
    function controllers(controllers){
        var numLoaded = 0;
        for (i = 0; i < controllers.length; i++) {
            $.ajaxSetup({async:false});
            $.getScript('js/controllers/' + controllers[i] + '.js').success(function(){
                numLoaded++;
                if (numLoaded == controllers.length) {
                    return true; //only return after all scripts are loaded, this is blocking, and will fail if all scripts aren't loaded.
                }
            });
        }
    }

    $routeProvider
        .when('/', {
            templateUrl: 'views/foo.html',
            resolve: {
                load: function () {
                    controllers(['foo'])
                }
            }
        })
        .when('/bar',{
            templateUrl: 'views/bar.html',
            controller: 'BarCtrl',
            resolve: {
                load: function () {
                    controllers(['bar','foo']) //you can load multiple controller files
                }
            }
        })
        .otherwise({
            redirectTo: document.location.pathname
        });
}]);

/views/foo.html

<section ng-controller='FooCtrl'>
    {{text}}
</section>

/views/bar.html

<section ng-controller='BarCtrl'>
    {{text2}}
</section>
<section ng-controller='FooCtrl'>
    {{text}}
</section>

/controllers/bar.js

app.registerCtrl('BarCtrl',function($scope){
    $scope.text2 = 'Test';
});
Discussion courtesy of: thecrazyrussian

////JConfig file--------

window.angularApp.config(function ($routeProvider,$controllerProvider,$compileProvider,$provide, azMessages) {

$routeProvider.when('/login', {
             resolve: {
                 load: ['$q', '$rootScope', function ($q, $rootScope) {
                     var deferred = $q.defer();
                     require([

                         //load required Js file here

                ], function () {
                    $rootScope.$apply(function () {
                        deferred.resolve();
                    });
                });
                     return deferred.promise;
                 } ]
             }
         });


  $routeProvider.otherwise({ redirectTo: '/login' });

    window.angularApp.components = {
        controller: $controllerProvider.register,
        service: $provide.service,
        directive: $compileProvider.directive
    }

//contoller declaration

angularApp.components.controller('DiscussionController',[function(){

}]);
Discussion courtesy of: chirag

This recipe can be found in it's original form on Stack Over Flow.