Composition using factory functions

factory-composition.js

var barker = function(state){
  return { bark: function(){ console.log('Woof, I am ' + state.name); } };
};

var driver = function(state){
  return { drive: function(){ 
    state.position = state.position + state.speed; 
    console.log(state.position);
  } };
};

var murderRobotDog = function(name){
  var state = {
    name: name,
    speed: 100,
    position: 0
  };

  return Object.assign(
    {},
    barker(state),
    driver(state)
  );
};

var bucky = murderRobotDog('bucky');
var goose = murderRobotDog('goose');