Value

• Provide a simple value

var myApp = angular.module('myApp', []);

myApp.value('myValue', 123);

myApp.controller('DemoController', ['myValue', function DemoController(myValue) {
  this.value= myValue;
}]);

Factory

Abilities

• Ability to use other services (have dependencies)
• Service initialization
• Delayed/lazy initialization

What if we want to compute the value?

Just like with the Value recipe, the Factory recipe can create a service of any type, whether it be a primitive, object literal, function, or even an instance of a custom type.

var myApp = angular.module('myApp', []);

myApp.value('a', 123);

myApp.factory('b',['a', function (a){
    return a * 2;
 }]);


myApp.controller('DemoController', ['a','b', function DemoController(a,b) {
  //a = 123
  //b = 246
  this.value = b;
}]);

Services

What if I want to be more OO and have a class called compute

var myApp = angular.module('myApp', []);

myApp.factory('b', function (){
    return new Compute();
 });

myApp.controller('DemoController', ['b', function DemoController(b) {
  //b = 246
  this.value = b.double(123);
}]);

function Compute() {
  this.double= function(a) {
      return a * 2;
  }
}

With services

var myApp = angular.module('myApp', []);

myApp.service('b', Compute);

myApp.controller('DemoController', ['b', function DemoController(b) {
  //b = 246
  this.value = b.double(123);
}]);


function Compute() {
  this.double= function(a) {
      return a * 2;
  }
}

Provider

What if I want to configure the Compute class before injection?

var myApp = angular.module('myApp', []);

myApp.provider('b', function() {
  var factor =  2;

  this.setFactor= function(s) {
     factor = s;
  }

  function Compute() {
     this.double= function(a) {
     	return a * factor;
    }
   }

  this.$get = function() {
    return new Compute();
  };
});

myApp.config(["bProvider", function(bProvider) {
  bProvider.setFactor(3);
}]);

myApp.controller('DemoController', ['b', function DemoController(b) {
  this.value = b.double(123);
}]);

You should use the Provider recipe only when you want to expose an API for application-wide configuration that must be made before the application starts. This is usually interesting only for reusable services whose behavior might need to vary slightly between applications.