CODEWITHSUNDEEP
javascriptjqueryhtmlangularjs
user3621014
user3621014

Reputation: 271

AngularJS - dynamic loading of external JS based on routes

I am trying to make a simple single page mobile app with multiple views and a next\back button to control each view. I am using the Angular Mobile UI library.

The basic mockup is as follows:

<html>
    <head>
        <link rel="stylesheet" href="mobile-angular-ui/dist/css/mobile-angular-ui-base.min.css">
        <link rel="stylesheet" href="mobile-angular-ui/dist/css/mobile-angular-ui-desktop.min.css">

        <script src="js/angular/angular.min.js"></script>
        <script src="js/angular/angular-route.min.js"></script>
        <script src="mobile-angular-ui/dist/js/mobile-angular-ui.min.js"></script>

        <script src="app/app.js"></script>
        <script src="app/firstController.js"></script>
        <script src="app/secondController.js"></script>
        <script src="app/thirdController.js"></script>

    </head>

    <body ng-app="demo-app">
        <div ng-view></div>

        <div ng-controller="nextBackController" class="navbar navbar-app navbar-absolute-bottom">
            <div class="btn-group justified">
              <a href="#/" class="btn btn-navbar btn-icon-only"><i class="fa fa-home fa-navbar"></i></a>
              <a href="#/second" class="btn btn-navbar btn-icon-only"><i class="fa fa-list fa-navbar"></i></a>
            </div>
        </div>

    </body>


</html>

App.js is as follows:

var app = angular.module('demo-app', [
  "ngRoute",
  "mobile-angular-ui"
]);

app.config(function($routeProvider) {
  $routeProvider.when('/', { controller: "firstController",
                             templateUrl: "views/first.html"});
  $routeProvider.when('/', { controller: "secondController",
                             templateUrl: "views/first.html"});
  $routeProvider.when('/', { controller: "thirdController",
                             templateUrl: "views/first.html"});
});

controllers = {};

controllers.nextBackController = function($scope, $rootScope) {
    //Simple controller for the next, back buttons so we just put it in app.js
};

app.controller(controllers);

firstController.js will contain something similar to:

controllers.firstController = function($scope) {
    //Do our logic here!!!
};

The problem is if you notice at the top of the HTML page I have to load all the controllers in. This is not scalable. I want each controller to be in it's own JS file and not have to statically load each one since the user may never even require that controller. Is there a way to dynamically load the actual JS file when switching routes? or can I stick a script tag at the top of my "first.html", "second.html", etc.

Upvotes: 22

Views: 44049

Answers (7)

BAYELK
BAYELK

Reputation: 83

I am not sure how it works in standard angular, however, you could use angular-ui-router:

Controllers are instantiated on an as-needed basis, when their corresponding scopes are created, i.e. when the user manually navigates to a state via a URL, $stateProvider will load the correct template into the view, then bind the controller to the template's scope.

https://github.com/angular-ui/ui-router/wiki

Upvotes: 1

Raja Khoury
Raja Khoury

Reputation: 3195

If I understand correctly you need to load specific scripts for each view? I am sharing this snippet from a personal project that uses ocLazyLoader a plugin that loads modules on demand.

var myApp = angular.module("myApp", [
"ui.router", 
"oc.lazyLoad",  
]);

then in your routing you could load dynamic JS / CSS files accordingly, in this example I am loading the UI Select plugin dependencies

myApp.config(['$stateProvider', '$urlRouterProvider', function($stateProvider, $urlRouterProvider) {

$stateProvider

  // State
    .state('demo', {
        url: "/demo.html",
        templateUrl: "views/demo.html",
        data: {pageTitle: 'demo page title'},
        controller: "GeneralController",
        resolve: {
            deps: ['$ocLazyLoad', function($ocLazyLoad) {
                return $ocLazyLoad.load([{
                    name: 'ui.select',
 // add UI select css / js for this state
                    files: [
                        'css/ui-select/select.min.css', 
                        'js/ui-select/select.min.js'
                    ] 
                }, {
                    name: 'myApp',
                    files: [
                        'js/controllers/GeneralController.js'
                    ] 
                }]);
            }]
        }
    })

Upvotes: 22

Lee Duckworth
Lee Duckworth

Reputation: 340

If you're familiar with Grunt:

https://github.com/ericclemmons/grunt-angular-templates

Use Grunt and the above build task to create one .js from all views. Include a watch task listener over all html files in a views directory. Whenever a change is made to any partial views, a "$templateCache" entry is created with all of the html in the file and a url to alias the cache. Your routes will point to the partial views in the same manner, but the html files do not need to be present. Only the .js file with the templates. The beauty of this is that it loads once and is available on the client side for the entire session. This cuts down on http calls and your traffic can be reduced to web service calls, only.

This is the example of a template from the github link, above:

angular.module('app').run(["$templateCache", function($templateCache) {
$templateCache.put("home.html",
// contents for home.html ...
);
...
$templateCache.put("src/app/templates/button.html",
// contents for button.html
);
}]);

If you're not familiar with Grunt

Check it out. It's pretty invaluable for automating builds, minification, concatenation, transpiling, etc...

http://gruntjs.com/

Upvotes: 7

AllJs
AllJs

Reputation: 1810

How to Install OCLazyLoad.

1. Download ocLazyLoad.js here

It can be found in the 'dist' folder of the git repository. You can also install it with bower install oclazyload or npm install oclazyload.

2. Add the module oc.lazyLoad to your application:

var myApp = angular.module("MyApp", ["oc.lazyLoad"]);

3. Load your JS files on demand, based on routes:

    myApp.controller("MyCtrl", function($ocLazyLoad){
       $ocLazyLoad.load('testModule.js');
    }});`

With $ocLazyLoad you can load angular modules, but if you want to load any component (controllers / services / filters / ...) without defining a new module it's entirely possible (just make sure that you define this component within an existing module).

There are multiple ways to use $ocLazyLoad to load your files, just choose the one that you prefer.

Also don't forget that if you want to get started and the docs are not enough, see the examples in the 'examples' folder!

Quick Start

Upvotes: 4

bto.rdz
bto.rdz

Reputation: 6720

I think the best way is use RequireJS, as mentioned here Does it make sense to use Require.js with Angular.js? It is totally allowed and it will let you reach what you are trying.

here is an example code

https://github.com/tnajdek/angular-requirejs-seed

Upvotes: 1

Evan Drewry
Evan Drewry

Reputation: 804

Unless your app is MASSIVE, you should REALLY avoid serving small js files individually. This will noticeably slow down your app, even if you were to figure out a way to lazily fetch files on an as-needed basis as you suggest in your question.

A much better way to do this (and the way used and suggested by the AngularJS team) is to have a BUILD PROCESS (you should use grunt for this) concatenate all your javascript files, and serve them as a single app.js file. This way you can maintain an organized code base with as many tiny js files as you want, but reduce script fetching to a single request.

Upvotes: 5

Gurjaspal
Gurjaspal

Reputation: 74

RequireJS can be really useful in this case. You can declare the dependencies of your JS files using RequireJS.

You can refer this simple tutorial.

Upvotes: 1

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