immutable-builder.js

var StudentClass = function(){
  this.name = "Some default name";
  this.age = undefined;
  this.address = {};
};
var StudentClassBuilder = new BuilderDecorator(StudentClass);

var student = new StudentClassBuilder()
  .name("John")
  .age(17)
  .address({postcode: "90210"})
  .build();

student.name();       // "John"
student.age();        // 17
student.address();    // {postcode: "90210"}