AngularJS Controllers

AngularJS controllers control the data of AngularJS applications.

AngularJS controllers are regular JavaScript Objects.

AngularJS Controllers

AngularJS applications are controlled by controllers.

The ng-controller directive defines the application controller.

A controller is a JavaScript Object, created by a standard JavaScript object constructor.

AngularJS Example

<div ng-app="myApp" ng-controller="myCtrl">

First Name: <input type="text" ng-model="firstName"><br>
Last Name: <input type="text" ng-model="lastName"><br>
<br>
Full Name: {{firstName + " " + lastName}}

</div>

<script>
var app = angular.module('myApp', []);
app.controller('myCtrl', function($scope) {
$scope.firstName = "John";
$scope.lastName = "Doe";
});
</script>

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Application explained:

The AngularJS application is defined by ng-app="myApp". The application runs inside the <div>.

The ng-controller="myCtrl" attribute is an AngularJS directive. It defines a controller.

The myCtrl function is a JavaScript function.

AngularJS will invoke the controller with a $scope object.

In AngularJS, $scope is the application object (the owner of application variables and functions).

The controller creates two properties (variables) in the scope (firstName and lastName).

The ng-model directives bind the input fields to the controller properties (firstName and lastName).

Controller Methods

The example above demonstrated a controller object with two properties: lastName and firstName.

A controller can also have methods (variables as functions):

AngularJS Example

<div ng-app="myApp" ng-controller="personCtrl">

First Name: <input type="text" ng-model="firstName"><br>
Last Name: <input type="text" ng-model="lastName"><br>
<br>
Full Name: {{fullName()}}

</div>

<script>
var app = angular.module('myApp', []);
app.controller('personCtrl', function($scope) {
$scope.firstName = "John";
  $scope.lastName = "Doe";
  $scope.fullName = function() {
    return $scope.firstName + " " + $scope.lastName;
  };
});
</script>

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Controllers In External Files

In larger applications, it is common to store controllers in external files.

Just copy the code between the <script> tags into an external file named personController.js:

AngularJS Example

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Another Example

For the next example we will create a new controller file:

angular.module('myApp', []).controller('namesCtrl', function($scope) {
  $scope.names = [
    {name:'Jani',country:'Norway'},
    {name:'Hege',country:'Sweden'},
    {name:'Kai',country:'Denmark'}
];
});

Save the file as namesController.js:

And then use the controller file in an application:

AngularJS Example

<div ng-app="myApp" ng-controller="namesCtrl">

<ul>
<li ng-repeat="x in names">
{{ x.name + ', ' + x.country }}
</li>
</ul>

</div>

<script src="namesController.js"></script>

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