Object creation pattern in JavaScript

Following are the few main JavaScript object creation patterns:

1. Factory Pattern 
2. Constructor Pattern 
3. Prototype Pattern 

1. Factory Pattern:

var carFactory = function(name, model, type){
 var obj = {};
 obj.name=name;
 obj.model=model;
 obj.type=type;
 
 obj.showCarDetails = function(){
  console.log("Name: "+ this.name);
  console.log("Model: "+ this.model);
  console.log("Type: "+ this.type);
 }
 return obj;
}

var car1 = carFactory('BMW','X5','SUV');
var car2 = carFactory('BMW','A6','Sedan');

car1.showCarDetails();
car2.showCarDetails();

• It is similar to a regular function only difference is that it would need to return a new instance of some object to be considered as "Factory" function.
• Ex. In above example we have created a new obj inside carFactory function and we are assigning the values (name,model,type) which we are passing to that object as a properties of it.
• Factory function doesn't use the "new" keyword unlike Constructor function.
• The problem with Factory function is that we cannot check whether the given object is created by certain factory. Ex. car instanceof carFactory // Return false

2. Constructor Pattern:

var CarConstructor = function(name, model, type){
 
 this.name=name;
 this.model=model;
 this.type=type;
 
 this.showCarDetails = function(){
  console.log("Name: "+ this.name);
  console.log("Model: "+ this.model);
  console.log("Type: "+ this.type);
 }
}

var car1 = new CarConstructor('BMW','X5','SUV');
var car2 = new CarConstructor('BMW','A6','Sedan');

car1.showCarDetails();
car2.showCarDetails();

• Here since constructor pattern not returning any object we have to use "new" keyword to create object of it.
• No need to return any as it'll implicitly return new object.
• So every time we create new object from CarConstructor function it'll create new instance of it.
• The functions execution context (this) will be set a new object.
• We can check whether the give object is created by constructor 
• i.e. car1 instanceof CarConstructor // return true

3. Prototype Pattern:

var carProto = function(){};

carProto.name="";
carProto.model="";
carProto.type="";

carProto.prototype.showCarDetails = function(){
  console.log("Name: "+ this.name);
  console.log("Model: "+ this.model);
  console.log("Type: "+ this.type);
}

var car1 = new carProto();

car1.name="Audi";
car1.model="A6";
car1.type="Sedan";

car1.showCarDetails();

• In prototype pattern the advantage of it over constructor pattern is that the showCarDetails function is part of prototype space and not directly the part of car1 object.