OLOO Composition - JavaScript

dog.js

'use strict';

const Dog = {
  name: 'Rocky',
  age: 2
};

const createDog = (name, age) => Object.assign(
  Object.create(Dog),
  { name, age }
)

exports.create = createDog;

index.js

'use strict';

const Dog = require('./dog');
const Person = require('./person');

// Factory methods!
const p = Person.create('Jenny Doe', 21);
const d = Dog.create('Puppy', 1);

// Composition over inheritance
p.dog = d;
console.log(d); // { name: 'Jenny Doe', age: 21, dog: { name: 'Puppy', age: 1 } }

programmer.js

'use strict';

const Dog = require('./dog');

const Programmer = {
  name: 'John Doe',
  age: 20
};

const createProgrammer = (name, age) => Object.assign(
  Object.create(Programmer),
  { name, age }
);

exports.create = createProgrammer;