My problem is I have one ng-app. Does that mean I have to do dependency injection for plugins I may not be using on that given view? Example I bring in ngTagsInput does that mean I have to do it even when the view doesn't call for it? That would mean I have to include that js for every view even if it doesn't use ngTagsInput.
I have a very large MVC .NET application and I am trying to figure out what is he best way to handle bringing in external plugins.
I have some code like so in our Main _Layout template:
<html ng-app="ourApp">
<head>
<!-- all of our includes are here -->
</head>
<body>
<directive></directive>
<anotherdirective></anotherdirective>
#RenderBody()
</body>
</html>
RenderBody is where MVC slides in our views from our mvc routing.That view may look like so:
<script src="~/Scripts/HomeAngular.js"></script>
<div ng-controller="HomeCtrl">
<directive3></directive3>
</div>
App JS:
var app = angular.module('ourApp', ['ngTagsInput']);
IS there a way I can get around having to inject ngTagsInput on every view page even if i don't need it?
There are several different ways to handle Dependency Injection (DI) in angular. In this first example, you simply define ngTagsInput before declaring the controller. If ngTagsInput is a service, for example, you'll need to return an object with methods that allow you to access the data inside of that service.
For example:
app.service('ngTagsInput', function($scope) {
var data = {};
return {
getData = function() {
return data;
},
setData = function(val) {
data = val;
}
};
});
app.controller('HomeCtrl', function($scope, ngTagsInput) {
// ...
$scope.tags = ngTagsInput; // whatever you want to do with it
});
However, there's a problem...
In the example above, if you run that code through a minifier, you'll get $scope turned into some variable (a, b, x, etc...) and angular wont know what to do with that.
In this method, we use an array. The last item in your array is your lambda function for the controller, which takes 1 argument for each previous item in the array:
app.controller('HomeCtrl', ['$scope', 'ngTagsInput', function(scp, ngTagIn) {
// ...
}]);
This code can be run through a minifier just fine, since the dependencies are strings in the array and can be renamed to anything you want inside the function's parameters.
DI also works in directives, factories, filters, and services with the same syntax; not just controllers and modules.
app.directive('HomeCtrl', ['$scope', 'ngTagsInput', function(scp, ngTagIn) {
// ...
}]);
Couldn't you break down your application further into smaller modules instead of just one. Then you can inject the smaller modules into the app module and only inject the ngTagsInput dependency on the modules that actually need it. That's how I typically break up my application by function or area.
Related
One of the great things about angular is that you can have independent Modules that you can reuse in different places. Say that you have a module to paint, order, and do a lot of things with lists. Say that this module will be used all around your application. And finally, say that you want to populate it in different ways. Here is an example:
angular.module('list', []).controller('listController', ListController);
var app = angular.module('myapp', ['list']).controller('appController', AppController);
function AppController() {
this.name = "Misae";
this.fetch = function() {
console.log("feching");
//change ListController list
//do something else
}
}
function ListController() {
this.list = [1, 2, 3];
this.revert = function() {
this.list.reverse();
}
}
<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.23/angular.min.js"></script>
<div class="app" ng-app="myapp" ng-controller="appController as App">
<div class="filters">
Name:
<input type="text" ng-model="App.name" />
<button ng-click="App.fetch()">Fetch</button>
</div>
<div class="list" ng-controller="listController as List">
<button ng-click="List.revert()">Revert</button>
<ul>
<li ng-repeat="item in List.list">{{item}}</li>
</ul>
</div>
</div>
Now, when you click on Fetch button, you'll send the name (and other filters and stuff) to an API using $http and so on. Then you get some data, including a list of items you want to paint. Then you want to send that list to the List module, to be painted.
It has to be this way because you'll be using the list module in diferent places and it will always paint a list and add some features like reordering and reversing it. While the filters and the API connection will change, your list behaviour will not, so there must be 2 different modules.
That said, what is the best way to send the data to the List module after fetching it? With a Service?
You should be using Angular components for this task.
You should create a module with a component that will be displaying lists and providing some actions that will modify the list and tell the parent to update the value.
var list = angular.module('listModule', []);
list.controller('listCtrl', function() {
this.reverse = function() {
this.items = [].concat(this.items).reverse();
this.onUpdate({ newValue: this.items });
};
});
list.component('list', {
bindings: {
items: '<',
onUpdate: '&'
},
controller: 'listCtrl',
template: '<button ng-click="$ctrl.reverse()">Revert</button><ul><li ng-repeat="item in $ctrl.items">{{ item }}</li></ul>'
});
This way when you click on "Revert" list component will reverse the array and execute the function provided in on-update attribute of HTML element.
Then you can simply set your app to be dependent on this module
var app = angular.module('app', ['listModule']);
and use list component
<list data-items="list" data-on-update="updateList(newValue)"></list>
You can see the rest of the code in the example
It is very simple. Please take a look at this small snippet. comments are added to highlight.
You can have a common module that contains all the data that needs to be shared across modules by two steps
adding module dependency
injecting corresponding provider in the respective module's controller
angular.module('commonAppData', []).factory('AppData',function(){
var a,b,c;
a=1;
return{
a:a,
b:b,
c:c
}
})
angular.module('list', ['commonAppData']).controller('listController', ListController);
var app = angular.module('myapp', ['list','commonAppData']).controller('appController', AppController);
function AppController(AppData) {
//assigning a variable
AppData.a=100;
this.name = "Misae";
this.fetch = function() {
console.log("feching");
//change ListController list
//do something else
}
}
function ListController(AppData) {
//Using the data sent by App Controller
this.variableA=AppData.a;
this.list = [1, 2, 3];
this.revert = function() {
this.list.reverse();
}
}
<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.23/angular.min.js"></script>
<div class="app" ng-app="myapp" ng-controller="appController as App">
<div class="filters">
Name:
<input type="text" ng-model="App.name" />
<button ng-click="App.fetch()">Fetch</button>
</div>
<div class="list" ng-controller="listController as List">
<b>Shared variable : {{List.variableA}}</b>
<br>
<button ng-click="List.revert()">Revert</button>
<ul>
<li ng-repeat="item in List.list">{{item}}</li>
</ul>
</div>
</div>
There are a few ways to handle objects acress multiple controllers. Here are two.
1. Using Angulars $rootScope
You can assign an object to $rootScopewhich will hold up all information. This object can be passed into every controller through Angulars dependency injection. Also you can listen up to changes on your object by watching it through $watch or $emit.
Using $rootScope is an easy way, but may lead to performance issues on larger applications.
2. Using services
Angular provides a possibility to share object through services. Instead of defining your object inside of your controller, you could also do that inside of a service. Doing so you could inject that service into any controller and use it's values across your application.
function AppController(listService) {
// reference to the injected data
}
function ListController(listService) {
// update data
}
There are many ways to pass data from one module to another module and many ppl have suggested different ways.
One of the finest way and cleaner approach is using a factory instead of polluting $rootScope or using $emit or $broadcast or $controller.If you want to know more about how to use all of this visit this blog on
Accessing functions of one controller from another in angular js
By simply inject the factory you have created in main module and add child modules as dependancy in main module, then inject factory in child modules to access the factory objects.
Here is a sample example on how to use factory for sharing data across the application.
Lets create a factory which can be used in entire application across all controllers to store data and access them.
Advantages with factory is you can create objects in it and intialise them any where in the controllers or we can set the defult values by intialising them in the factory itself.
Factory
app.factory('SharedData',['$http','$rootScope',function($http,$rootScope){
var SharedData = {}; // create factory object...
SharedData.appName ='My App';
return SharedData;
}]);
Service
app.service('Auth', ['$http', '$q', 'SharedData', function($http, $q,SharedData) {
this.getUser = function() {
return $http.get('user.json')
.then(function(response) {
this.user = response.data;
SharedData.userData = this.user; // inject in the service and create a object in factory ob ject to store user data..
return response.data;
}, function(error) {
return $q.reject(error.data);
});
};
}]);
Controller
var app = angular.module("app", []);
app.controller("testController", ["$scope",'SharedData','Auth',
function($scope,SharedData,Auth) {
$scope.user ={};
// do a service call via service and check the shared data which is factory object ...
var user = Auth.getUser().then(function(res){
console.log(SharedData);
$scope.user = SharedData.userData;// assigning to scope.
});
}]);
In HTML
<body ng-app='app'>
<div class="media-list" ng-controller="testController">
<pre> {{user | json}}</pre>
</div>
</body>
It depends on the circumstance. Is there a parent child relationship? Is the relationship unknown, or you simply want to avoid having to worry about it at all?
I think this post lays it out well (it always seems to be helpful):
http://mean.expert/2016/05/21/angular-2-component-communication/
AngularJS provides $on, $emit, and $broadcast services for event-based communication between controllers.
So, if we want to pass data from the inner controller (listController) to outer controller (appController) then we have to use $emit. It dispatches an event name upwards through the scope hierarchy and notify to the registered $rootScope.
Working Plunker : https://plnkr.co/edit/szf9jHvvOPLOvQc5sQI2?p=preview
This plunker is not as per the exact requirement as I don't know the API response but this sample plunker describe the problem statement.
I think you can use the publisher-subscriber pattern implemented in $rootScope.
In the ListController you have to inject $rootScope and after that you have to subscribe to an arbitrary called event that could have the pattern _data_received
$rootScope.$on('ingredients_data_received', function(ingredients) { prepare_recipe();});
so in your AppController you have to call $rootScope.$emit once the data of that list has been received
$rootScope.$emit('ingredients_data_received', ingredients);
This is just a way to pass data, you can also push those data or the promise in a $rootScope property but this is not a good practice, or you can create your own Service that manage the data for you (remember that you are working with a frontend framework so the controller has to control the view, the business logic has to be transfered to a service, not to a crontroller).
I like to use angular resource with a caching layer to persist data to multiple controllers using a singular method. This has a few benefits namely any controller has the same entry point to data. Keep in mind sometimes you need to fetch fresh data when navigating from one portion of the site to another so persisting http data is not always ideal.
'use strict';
(function() {
angular.module('customModule')
.service('BookService', BookService);
BookService.$inject = ['$resource'];
function BookService($resource) {
var BookResource = $resource('/books', {id: '#id'}, {
getBooks: {
method: 'GET',
cache: true
}
});
return {
getBooks: getBooks
};
function getBooks(params) {
if (!params) {
params = {};
}
return BookResource.getBooks(params).$promise;
}
}
})();
In any controller
BookService.getBooks().then(function(books) {
//books will be cached so invoking the call will return the same set of data anywhere
});
Services in angular are used to share functionality between components. Please try to keep them simple and with a single responsibility/purpose.
An idea would be creating a store service that will cache every response from the api in your application. Then you don't have to request it every time.
Hope it helps! ;)
I'm new to AngularJS and I would like to understand more about the dependencies that are being injected by default. While reading through code I've noticed that sometimes dependencies are explicitly declared beforehand, and sometimes they aren't. For example:
someModule.controller('MyController', ['$scope', 'someService', function($scope, someService) {
// ...
}]);
Gives the same results as:
someModule.controller('MyController', function($scope, someService) {
// ...
});
How does this work? Is Angular assuming that the modules being injected are named the same as the variables in the parameters?
Also, strangely enough, if you do specify the dependencies that are going to be injected, you must specify all of them and in the right order, otherwise nothing will work. For example, this is broken code:
someModule.controller('MyController', ['someService', '$scope', function($scope, someService) {
// Won't give us any errors, but also won't load the dependencies properly
}]);
Can someone clarify to me how is this whole process working? Thank you very much!!
Yes, dependency injection in Angular works via the names of the components you (and Angular - for the internal ones) registered.
Below is an example showing how a service is registered and injected into a controller using several different annotations. Please note that dependency injection always works the same in Angular, i.e. it doesn't matter if you are injecting something into a controller, a directive or a service.
app.service('myService', function () {
// registering a component - in this case a service
// the name is 'myService' and is used to inject this
// service into other components
});
Two use (inject) this component in other components, there are three different annotations I am aware of:
1. Implicit Annotation
You can either specify a constructor function which takes as parameters all the dependencies. And yes, the names need to be the same as when these components were registered:
app.controller('MyController', function ($http, myService) {
// ..
});
2. Inline Array Annotation
Or you can use a notation using an array, where the last parameter is the constructor function with all the injectables (variable names do not matter in this case). The other values in the array need to be strings that match the names of the injectables. Angular can this way detect the order of the injectables and do so appropriately.
app.controller('MyController', ['$http', 'myService', function ($h, m) {
/* Now here you can use all properties of $http by name of $h & myService by m */
// Example
$h.x="Putting some value"; // $h will be $http for angular app
}]);
3. $inject Property Annotation
A third option is to specify the $inject-property on the constructor function:
function MyController($http, myService) {
// ..
}
MyController.$inject = ['$http', 'myService'];
app.controller('MyController', MyController);
The reason why the last two options are available, at least as far as I know, is due to issues which occured when minifying the JavaScript files which led to the names of the parameters being renamed. Angular then wasn't able to detect what to inject anymore. In the second two cases the injectables are defined as strings, which are not touched during minification.
I would recommend to use version 2 or 3, as version 1 won't work with minification/obfuscation. I prefer version 3 as from my point of view it is the most explicit.
You can find some more detailed information in the internet, e.g. on the Angular Developer Guide.
Just to provide a different sort of answer, as to the how inline/implicit dependencies work in AngularJS. Angular does a toString on the provided function and parses the parameter names from the string which is produced. Example:
function foo(bar) {}
foo.toString() === "function foo(bar) {}"
References:
source code
AngularJS Dependency Injection - Demystified
I'm trying to use lodash use it at ng-repeat directives, in this way:
<div ng-controller="GridController" ng-repeat="n in _.range(5)">
<div>Hello {{n}}</div>
</div>
Being GridController:
IndexModule.controller('GridController', function () {
this._ = _
})
However is not working and so, nothing being repeated. If I change the directive to ng-repeat="i in [1,2,3,4,5]" it'll work.
lodash is already included via <script> at <header> before angular. How can I make it work?
I prefer to introduce '_' globally and injectable for tests, see my answer to this question
Use underscore inside controllers
var myapp = angular.module('myApp', [])
// allow DI for use in controllers, unit tests
.constant('_', window._)
// use in views, ng-repeat="x in _.range(3)"
.run(function ($rootScope) {
$rootScope._ = window._;
});
I just wanted to add some clarification to #beret's and #wires's answer. They definitely helped and got the jist of it but getting the whole process in order might suit someone. This is how I set up my angular environment with lodash and got it working with yeoman gulp-angular to serve properly
bower install lodash --save (This adds to bower and a saves to bower json)
modify bower json to have lodash load before angular does. (This helps if you're using gulp inject and don't want to manually put it into index.html. otherwise put it into the index.html before the angular link)
Make a new constant per #wires's direction.
'use strict';
angular.module('stackSample')
// lodash support
.constant('_', window._);
Inject into any angular service, filter, or controller as you would anything else:
.filter('coffeeFilter', ['_', function(_) {...}]);
To throw it into some angular html view just inject it into the controller and assign a scope variable to it:
.controller('SnesController', function ($scope, _) {
$scope._ = _;
})
Hope this helps someone set up their site. :)
ng-repeat requires an Angular expression, which has access to Angular scope variables. So instead assigning _ to this, assign it to the $scope object you inject into the controller:
IndexModule.controller('GridController', function ($scope) {
$scope._ = _;
})
Demo
I am not sure what version of Angular you are using. Looks like you should have just used the 'Controller as' syntax when you use 'this' to access variables in the dom.
Here is the solution with this and not using scope.
http://plnkr.co/edit/9IybWRrBhlgQAOdAc6fs?p=info
<body ng-app="myApp" ng-controller="GridController as grid">
<div ng-repeat="n in grid._.range(5)">
<div>Hello {{n}}</div>
</div>
</body>
As i tried to learn some Angular in the past weeks, i have adopted a certain application architecture.
Assuming a intermediate large SPA, i create the view and apply a maincontroller:
<html ng-app="app">
<body ng-controller="appCtrl">
<!-- All of the view goes in here -->
</body>
</html>
Now i think about the stuff that my application will have to do. Assuming that this one would have to store some data and working with it, i would create a provider to build a "class".
var data = angular.module('data', []);
data.provider('$dataObject',function(){
this.$get = function($http){
function DataObject(){
var field = "testvalue";
var object = {
// ...
}
}
DataObject.prototype.processData = function(){
// do something
};
return {
Shipment: function(){
return new Shipment();
}
}
}
});
I would then create an instance of that class in my maincontroller, storing all of the necessary data from the view into that object, processing it by calling the class methods.
If the application would need another functionality, e.g a dialog to pick some stuff, i would repeat the steps above and create a class for that dialog.
Now, while i am quite comfortable to do things that way, i still wonder if someone would consider this bad practice, and if so, why is that and what could i do better?
Creating services/providers for your models/data (with APIs to expose the data), and then injecting them into controllers is the "Angular way."
When I design an angular app, I think about the models I need and create services for them. I then (or in parallel) think about the views and design those. I normally create custom directives at this point also. Lastly, each view gets a controller, whose job it is to glue the models/data from the services that the view needs. (Make controllers as thin as possible.)
New in angularJS, I would like to know what are the pros and cons between the codes below?
Which is recommended to use?
$routeProvider.when('foo', {
templateUrl: 'foo.html',
controller: fooCtrl
function fooCtrl() {
//something here
}
});
or
$routeProvider.when('foo', {
templateUrl: 'foo.html'
});
app.controller("fooCtrl", function() {
//something here
});
//in html
<div ng-controller="fooCtrl"></div>
I prefer the second approach, and use it when developing our application.
It is the elegant way of coding , seperating your routes-configuration, module-wiring etc from the Controllers. we can write the routes-config in a main file say app.coffee [I use coffeescript] defining like
routesConfig = ($route) ->
$route.when('/employees',
{templateUrl: 'employee.employeeView.html'})
Define the routesconfig and wiring modules [eg: employee.employeeController] here.
modules = ['employee.employeeController', 'user.userController']
you can create, start your angular application from here,
m = angular.module('app', modules)
m.config['$route', routesConfig]
Now you can specify the Controllers seperately, say in employeeController.coffee
name = 'employee.employeeController'
mod = angular.module(name, [])
mod.controller(name, [
'$scope'
'$log'
($scope, $log) ->
$scope.name = 'java'
In your View, say employeeView.html
<div ng-controller="employee.employeeController">
<div class ="info">
Name is {{name}}
</div>
Basically we seperated Controllers, View , application configuration from each other.
To add something specific to your question,
If you are using the first approach, then probably you are using your controller as a Route Controller, and in
second approach , it is a View Controller.
In both cases, controller will be instantiated for the mentioned route.
For instance, I have a main page index.html and i am adding many views (ng-view) in the basic html template.
If you have two different sections of view in this template say 'section1' and 'section2' and each of them are included
with ng-view, then you probably need two different controllers, and is good to define them using the second approach.
Use this type of controller to initialize the scope with data,functions,watches etc and refer the controller in your view using ng-controller.
If you have a section, say 'section1' [representing the main html page] that is included via ng-view which encapsulates both section1 and section2,
then that view needs route controller.
Do not use both the approaches for a single view/route as it would result in creating two instances of same controller
for the same route.
I like to add two links here which eloborates this (your query) and address this query (problem in defining controllers in two places)
https://groups.google.com/forum/?fromgroups=#!topic/angular/52zE0ibOAgk
AngularJS can a $on method be called more than once for a single $broadcast?