allernhwkim originally posted an answer on this question linking to his blog, however a moderator deleted it. It's the only post I've found which doesn't just tell you how to do the same thing with service, provider and factory, but also tells you what you can do with a provider that you can't with a factory, and with a factory that you can't with a service.
Directly from his blog:
app.service('CarService', function() {
this.dealer="Bad";
this.numCylinder = 4;
});
app.factory('CarFactory', function() {
return function(numCylinder) {
this.dealer="Bad";
this.numCylinder = numCylinder
};
});
app.provider('CarProvider', function() {
this.dealerName = 'Bad';
this.$get = function() {
return function(numCylinder) {
this.numCylinder = numCylinder;
this.dealer = this.dealerName;
}
};
this.setDealerName = function(str) {
this.dealerName = str;
}
});
This shows how the CarService will always a produce a car with 4 cylinders, you can't change it for individual cars. Whereas CarFactory returns a function so you can do new CarFactory in your controller, passing in a number of cylinders specific to that car. You can't do new CarService because CarService is an object not a function.
The reason factories don't work like this:
app.factory('CarFactory', function(numCylinder) {
this.dealer="Bad";
this.numCylinder = numCylinder
});
And automatically return a function for you to instantiate, is because then you can't do this (add things to the prototype/etc):
app.factory('CarFactory', function() {
function Car(numCylinder) {
this.dealer="Bad";
this.numCylinder = numCylinder
};
Car.prototype.breakCylinder = function() {
this.numCylinder -= 1;
};
return Car;
});
See how it is literally a factory producing a car.
The conclusion from his blog is pretty good:
In conclusion,
--------------------------------------------------- | Provider| Singleton| Instantiable | Configurable| --------------------------------------------------- | Factory | Yes | Yes | No | --------------------------------------------------- | Service | Yes | No | No | --------------------------------------------------- | Provider| Yes | Yes | Yes | ---------------------------------------------------
Use Service when you need just a simple object such as a Hash, for example {foo;1, bar:2} It’s easy to code, but you cannot instantiate it.
Use Factory when you need to instantiate an object, i.e new Customer(), new Comment(), etc.
Use Provider when you need to configure it. i.e. test url, QA url, production url.
If you find you're just returning an object in factory you should probably use service.
Don't do this:
app.factory('CarFactory', function() {
return {
numCylinder: 4
};
});
Use service instead:
app.service('CarService', function() {
this.numCylinder = 4;
});