AngularJS Services
In AngularJS you can make your own service, or use one of the many built-in services.
What is a Service?
In AngularJS, a service is a function, or object, that is available for, and limited to, your AngularJS application.
AngularJS has about 30 built-in services. One of them is the $location
service.
The $location service has methods which return information
about the location of the current web page:
Example
Use the $location service in a controller:
var app = angular.module('myApp', []);
app.controller('customersCtrl',
function($scope, $location) {
$scope.myUrl = $location.absUrl();
});
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Note that the $location service is passed in to the controller
as an argument. In order to use the service in the controller, it must be
defined as a dependency.
Why use Services?
For many services, like the $location service, it seems like you
could use objects that are already in the DOM, like the window.location
object, and you could, but it would have some limitations, at least for your
AngularJS application.
AngularJS constantly supervises your application, and for it to handle changes
and events properly, AngularJS prefers that you use the $location
service instead of the window.location object.
The $http Service
The $http service is one of the most common used services in AngularJS
applications. The service makes a request to the server, and lets your
application handle the response.
Example
Use the $http service to request data from the server:
var app = angular.module('myApp', []);
app.controller('myCtrl',
function($scope, $http) {
$http.get("welcome.htm").then(function
(response) {
$scope.myWelcome
= response.data;
});
});
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This example demonstrates a very simple use of the $http service. Learn more
about the $http service in the AngularJS Http
Tutorial.
The $timeout Service
The $timeout service is AngularJS' version of the
window.setTimeout function.
Example
Display a new message after two seconds:
var app = angular.module('myApp', []);
app.controller('myCtrl',
function($scope, $timeout) {
$scope.myHeader = "Hello
World!";
$timeout(function () {
$scope.myHeader = "How are you today?";
}, 2000);
});
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The $interval Service
The $interval service is AngularJS' version of the
window.setInterval function.
Example
Display the time every second:
var app = angular.module('myApp', []);
app.controller('myCtrl',
function($scope, $interval) {
$scope.theTime = new
Date().toLocaleTimeString();
$interval(function () {
$scope.theTime = new Date().toLocaleTimeString();
},
1000);
});
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Create Your Own Service
To create your own service, connect your service to the module:
Create a service named hexafy:
app.service('hexafy', function() {
this.myFunc = function (x) {
return x.toString(16);
}
});
To use your custom made service, add it as a dependency when defining the controller:
Example
Use the custom made service named hexafy to convert a number
into a hexadecimal number:
app.controller('myCtrl', function($scope, hexafy) {
$scope.hex
= hexafy.myFunc(255);
});
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Use a Custom Service Inside a Filter
Once you have created a service, and connected it to your application, you can use the service in any controller, directive, filter, or even inside other services.
To use the service inside a filter, add it as a dependency when defining the filter:
The service hexafy used in the filter myFormat:
app.filter('myFormat',['hexafy', function(hexafy) {
return function(x) {
return
hexafy.myFunc(x);
};
}]);
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You can use the filter when displaying values from an object, or an array:
<ul>
<li ng-repeat="x in counts">{{x | myFormat}}</li>
</ul>
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