Angularjs directive

Directives are the most important feature of AngularJS . Before we jump into how to create custom directive, first to understand the relationship between directive Scope and controllers is very important to help your create custom directives.

In angularjs, directive sit inside controllers, so when you create a custom directive, you must first create an angularjs module and controller first.

When you create a directive, angularjs provide 3 different scope for your to use:

Shared scope when you create a directive don’t specify the scope then it will be shared scope.So your controller and your directive has the same scope, like in c# field, the controller and the directive have point it point to the same object.Create shared scope you must be very careful, because the directive could override the controller scopes.

//shared scope example
angular.module('app', []);

angular.module('app').controller('mainCtrl', function($scope) {
  $scope.Todo = {
    title: 'your title',
    address: 'your address',
    description: 'your description'


angular.module('app').directive('toDoList', function() {
  return {// in here I didn't specify the scope, so it will be shared scope
    templateUrl: "todoList.html",
    restrict: "E"

////event without define the scope in here, but the directive already share the 
//mainCtrol scope here
Description: {{description}}

Inherited scope when you create a directive return scope:true then it will create a inherited scope, so the parent scope(controller scope) will visible in the child scope( directive scope), but the  directive can’t override the parent scope. for example if you have scope.message = “parent message”; in the directive you create a scope.message = “child messages” it won’t override the parent scope, in there view if you use {{messages}} output is parent message, but if you use shared scope, in the directive template the output will be {{child messages}}

//shared scope example
angular.module('app', []);

angular.module('app').controller('mainCtrl', function($scope) {
  $scope.message = "parent message";

angular.module('app').directive('messagesView', function() {
  return {
    templateUrl: "messagesView.html",
    restrict: "E",
    scope:true,  // this is make the directive scope inherit from the mainCtrl
      $scope.message = "child message"; 

 } } })
{{message}} // output will be parent message 

Isolated scope: it allow the developer to encapsulate the data to your custom directive use only.

angular.module('app').directive('removeTodo', function() {
  return {
    restrict: 'E',
    templateUrl: 'removeTodo.html',
    scope: {
      todos: '=' //todos is only visible in your directive scope
    controller: function($scope) {
      $scope.removeItem = function(todo) {
        var idx = $;
        if(idx > -1) {
          $, 1);

And attach the whole angularjs directive structionangularjs-directive


Angularjs Service — Value and Constant Services

Value Services

  • Shorthand for factory with no parameters
  • Cannot be injected into a module configuration function
  • Can be overridden by an AngularJS decorator

Example using value

        .value('clientId', 'a12345654321x');

Constant Services

  • Simply registers service with injector, no factory/provider calls
  • Can be injected into a module configuration function
  • Cannot be overridden by an AngularJSdecorator


        .constant('constants', {
            APP_TITLE: 'My App',
            APP_DESCRIPTION: 'Description here.',
            APP_VERSION: '0.0.1'

ANGULARJS SERVICES – Factory and Services

Using the factory function on the provide service is usually a much simpler option than using provider, if you don’t need to configure the underlying provider object. The snippet of code here is the Angular source code for the factory function.

function factory(name, factoryFn, enforce) { 
	return provider(name, { 
		$get: enforce !== false ? enforceReturnValue(name, factoryFn) : factoryFn 

You can see that all it really does is call the provider function and assign the function you pass to the factory function as the value of the get property on the provider.

Internally, it creates and passes the parameter name, enforce, just as a safety check to make sure the function passed to it actually returns an object. To use the factory function, you just pass it a name as the first parameter, like the provider function, and the second parameter is a function that will return an object that represents the service instance. If you don’t need to configure the provider, like previous post sample demo code, then using the factory function will be a much simpler and readable way to create your services.

The next service creation function we’ll look at is actually named service. It’s just a very thin wrapper around the factory function we just saw. The only difference is that the function you passed to the service method will be treated as a constructor function and called with the JavaScript “new” operator.

The snippet here is the Angular source code for the service function.

	function service(name, constructor) { 
	  return factory(name, ['$injector', function($injector) {  
	   return $injector.instantiate(constructor); 

It uses the instantiate method of the injector to call the function you pass to the service method. The instantiate method will then use the “new” operator to execute the function that creates the service. You would use the service method instead of the factory method if you specifically needed your function to be treated as a constructor and called with the “new” operator. There are several reasons why you may want that behavior. One is if you have defined an inheritance hierarchy in your code. Creating an instance with “new” will make sure that your instantiated object properly inherits from its prototypes.

Here is the example you must use the services instead of factory.

        .service('logger', MyLogger);

    function LoggerBase() { }

    LoggerBase.prototype.output = function(message) {
        console.log('LoggerBase: ' + message);

    function MyLogger() {;

        this.log = function(obj) {
            console.log('Book: ' +;

    MyLogger.prototype = Object.create(LoggerBase.prototype);

only now I can use the output function, but using factory it won’t.

 app.config(['$logProvider',  function ( $logProvider) {
        $logProvider.output('what ever here!');

to be continue……..


AngularJs Services – Provider

Try to help reader to understanding of Angular service, and the confidence to choose the right technique when come to use it .

There are five functions you can use to create an Angular service. All of these functions may be called on the built-in provide service. All of them are also exposed on the module object as a convenience. The most fundamental service creation function is the provider function. Creating services with it allows you to explicitly create a configurable provider object. The provider knows how to create the resulting service. The remaining four functions all internally call the provider function.

Now start with the lower provider services, here is the example code for using the angularjs provider service:

app.provider('myApp', [function () {

        var includeVersion = false;
        this.setIncludeVersion = function (value) {
            includeVersion = value;

        this.$get = function () {
            var appName = 'My first App";
            var version = '0.0.1';
            if (includeVersion) {
                appName += ' ' + version;
            var appDesc = 'here is some description';
            return {
                appName: appName,
                appDesc: appDesc


See in here you could pass a parameter to decided some basic setting, just like website have a web.config file, so the app in the client side also have their own config file.
Be aware of when you use the provider function the angularjs will automatic add the Provider to it, so when you use it need use the name with myAppProvider.

   app.config(['myAppProvider', function (bookingAppProvider) {


to be continue….