Builder

Separates object construction from its representation

• Separate the construction of a complex object from its representation so that the same construction process can create different representations.

• The different Builders must implement the same multistep interface for the Director to be able to step through the assembly process.

• Simply, combining multiple simple objects to make multiple combination of complex objects.

EX:
function Shop() {
    this.construct = function(builder) {
        builder.step1();
        builder.step2();
        return builder.get();
    }
}
 
function CarBuilder() {
    this.car = null;
 
    this.step1 = function() {
        this.car = new Car();
    };
 
    this.step2 = function() {
        this.car.addParts();
    };
 
    this.get = function() {
        return this.car;
    };
}
 
function TruckBuilder() {
    this.truck = null;
 
    this.step1 = function() {
        this.truck = new Truck();
    };
 
    this.step2 = function() {
        this.truck.addParts();
    };
 
    this.get = function() {
        return this.truck;
    };
}
 
function Car() {
    this.doors = 0; 
    this.addParts = function() {
        this.doors = 4;
    };
}
 
function Truck() {
    this.doors = 0; 
    this.addParts = function() {
        this.doors = 2;
    };
}
 
function run() {
    var shop = new Shop();
    var carBuilder = new CarBuilder();
    var truckBuilder = new TruckBuilder();
    var car = shop.construct(carBuilder);
    var truck = shop.construct(truckBuilder);
}