Wednesday, November 4, 2015

AngularJS - Services

Services

Angular services are substitutable objects that are wired together using dependency injection (DI). You can use services to organize and share code across your app.
Angular services are:
  • Lazily instantiated – Angular only instantiates a service when an application component depends on it.
  • Singletons – Each component dependent on a service gets a reference to the single instance generated by the service factory.
Angular offers several useful services (like $http), but for most applications you'll also want to create your own.


Using a Service

To use an Angular service, you add it as a dependency for the component (controller, service, filter or directive) that depends on the service. Angular's dependency injection subsystem takes care of the rest.

-----------------------
index.html
-----------------------
 <!doctype html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Example - example-example45-production</title>
  <script src="//ajax.googleapis.com/ajax/libs/angularjs/1.5.0-beta.1/angular.min.js"></script>
  <script src="script.js"></script>
</head>
<body ng-app="myServiceModule">
  <div id="simple" ng-controller="MyController">
  <p>Let's try this simple notify service, injected into the controller...</p>
  <input ng-init="message='test'" ng-model="message" >
  <button ng-click="callNotify(message);">NOTIFY</button>
  <p>(you have to click 3 times to see an alert)</p>
</div>
</body>
</html>


 -------------------------
script.js
-------------------------

(function(angular) {
  'use strict';
angular.
 module('myServiceModule', []).
  controller('MyController', ['$scope','notify', function ($scope, notify) {
    $scope.callNotify = function(msg) {
      notify(msg);
    };
  }]).
 factory('notify', ['$window', function(win) {
    var msgs = [];
    return function(msg) {
      msgs.push(msg);
      if (msgs.length == 3) {
        win.alert(msgs.join("\n"));
        msgs = [];
      }
    };
  }]);
})(window.angular);


Some Sample service in Angular JS

$log
$exceptionHandler
$http
$route
$scope

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