Understanding AngularJS Factory, Service and Provider

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06 Aug 2022

Advanced

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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...

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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.