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Understanding AngularJS Factory, Service and Provider

06 Aug 2022
Advanced
110K Views

In AngularJS, services are reusable singleton objects that are used to organize and share code across your app. They can be injected into controllers, filters, directives. AngularJS provides you three ways : service, factory and provider to create a service.

Factory

A factory is a simple function which allows you to add some logic before creating the object. It returns the created object.

Syntax

app.factory('serviceName',function(){ return serviceObj;})

Creating service using factory method

 <script>
//creating module
 var app = angular.module('app', []);

 //define a factory using factory() function
app.factory('MyFactory', function () {

 var serviceObj = {};
 serviceObj.function1 = function () {
 //TO DO:
 };

 serviceObj.function2 = function () {
 //TO DO:
 };

 return serviceObj;
});
 </script>

When to use

It is just a collection of functions like a class. Hence, it can be instantiated in different controllers when you are using it with constructor function.

Service

A service is a constructor function which creates the object using new keyword. You can add properties and functions to a service object by using this keyword. Unlike factory, it doesn’t return anything.

Syntax

app.service('serviceName',function(){})

Creating service using service method

 <script>
//creating module
var app = angular.module('app', []);

//define a service using service() function
app.service('MyService', function () {
 this.function1 = function () {
 //TO DO:
 };

 this.function2 = function () {
 //TO DO:
 };
 });
 </script>

When to use

It is a singleton object. Use it when you need to share a single object across the application. For example, authenticated user details.

Provider

A provider is used to create a configurable service object. It returns value by using $get() function.

Syntax

//creating a service
app.provider('serviceName',function(){});

//configuring the service
app.config(function(serviceNameProvider){});

Creating service using provider method

 <script>
//define a provider using provider() function
app.provider('configurableService', function () {
 var name = '';
 this.setName = function (newName) {
 name = newName;
 };
 this.$get = function () {
 return name;
 };
});

//configuring provider using config() function
app.config(function (configurableService) {
 configurableService.setName('www.dotnet-tricks.com');
});
 </script>

When to use

When you need to provide module-wise configuration for your service object before making it available.

AngularJS : Factory, Service and Provider with example

<html>
<head>
 <title>AngularJS Service Factory and Providers</title>
 <script src="lib/angular.js"></script>
</head>
<body>
 <div class="container" style="padding-top:20px;">
 <div ng-app="myApp" ng-controller="myController">
 <p>From Service: {{serviceName}}</p>
 <p>From Factory: {{factoryName}}</p>
 <p>From Provider: {{providerName}}</p>
 </div>
 </div>
 <script>
 //defining module
 var app = angular.module('myApp', []);

 //defining service
 app.service('myService', function () {
 this.name = '';
 this.setName = function (newName) {
 this.name = newName;
 return this.name;
 };
 });

 //defining factory
 app.factory('myFactory', function () {
 var serviceObj = {};
 serviceObj.name = '';
 serviceObj.setName = function (newName) {
 serviceObj.name = newName;
 };
 return serviceObj;
 });

 //defining provider
 app.provider('configurable', function () {
 var privateName = '';
 this.setName = function (newName) {
 privateName = newName;
 };
 this.$get = function () {
 return {
 name: privateName
 };
 };
 });

 //configuring provider
 app.config(function (configurableProvider) {
 configurableProvider.setName("Saksham Chauhan");
 });

 //defining controller
 app.controller('myController', function ($scope, myService, myFactory, configurable) {
 $scope.serviceName = myService.setName("Saksham Chauhan");

 myFactory.setName("Saksham Chauhan");
 $scope.factoryName = myFactory.name;

 $scope.providerName = configurable.name;
 });
 </script>
</body>
</html>

How it works...

What do you think?

I hope you will enjoy the AngularJS factory, service and provider functions while developing your app with AngularJS. I would like to have feedback from my blog readers. Your valuable feedback, question, or comments about this article are always welcome.

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