Sunday, 26 April 2015

AngularJS Modules



An AngularJS module defines an application.
A module is a container for the different parts of an application.
All application controllers should belong to a module.

A Module With One Controller:
This application ("myApp"), has one controller ("myCtrl"):
<!DOCTYPE html>
<html>

<head>
<script src="http://ajax.googleapis.com/ajax/libs/angularjs/1.3.14/angular.min.js"></script>
</head>

<body>

<div ng-app="myApp" ng-controller="myCtrl">
{{ firstName + " " + lastName }}
</div>

<script>
var app = angular.module("myApp", []);

app.controller("myCtrl", function($scope) {
    $scope.firstName = "Ravi";
    $scope.lastName = "Gupta";
});
</script>

</body>
</html>


Modules and Controllers in Files:
It is common in AngularJS applications to put the module and the controllers in JavaScript files.
In this example, "myApp.js" contains an application module definition, while "myCtrl.js" contains the controller:
<!DOCTYPE html>
<html>

<head>
<script src="http://ajax.googleapis.com/ajax/libs/angularjs/1.3.14/angular.min.js"></script>
</head>

<body>

<div ng-app="myApp" ng-controller="myCtrl">
{{ firstName + " " + lastName }}
</div>

<script src="myApp.js"></script>
<script src="myCtrl.js"></script>

</body>
</html>

myApp.js

var app = angular.module("myApp", []);
The [] parameter in the module definition can be used to define dependent modules.

myCtrl.js

app.controller("myCtrl", function($scope) {
    $scope.firstName = "Ravi";
    $scope.lastName= "Gupta";
});


Functions can Pollute the Global Namespace:
Global functions should be avoided in JavaScript. They can easily be overwritten or destroyed by other scripts.
AngularJS modules reduces this problem, by keeping all functions local to the module.

When to Load the Library?
In all our examples, the AngularJS library is loaded in the <head> section.
A common advise for HTML applications, is to place scripts at the very bottom of the <body> element.
But, in many AngularJS examples, you will see the library in the <head> element.
This is because calls to angular.module can only be compiled after the library has been loaded.
Another solution is to load the AngularJS library in the <body> element, before your own AngularJS scripts:
<!DOCTYPE html>
<html>
<body>

<div ng-app="myApp" ng-controller="myCtrl">
{{ firstName + " " + lastName }}
</div>

<script src="http://ajax.googleapis.com/ajax/libs/angularjs/1.3.14/angular.min.js"></script>

<script>
var app = angular.module("myApp", []);

app.controller("myCtrl", function($scope) {
    $scope.firstName = "Ravi";
    $scope.lastName = "Gupta";
});
</script>

</body>
</html>



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