Just playing around with object.assign

object-assign.js

(function(){

  window.Player = function(config = {}){
    
    this.defaults = {
    		name: "Karim Benzema",
        age: 29,
        position: "CF",
        club: "Real Madrid CF"
    }
    
    this.options = Object.assign({}, this.defaults, config)
    
  }
  
   Player.prototype.introduce = function(){
    	console.log(`Hey my name is ${this.options.name}, I'm ${this.options.age} years old, I play as a ${this.options.position} for ${this.options.club}`)
   }
  
})()

const Nasri = new Player({
	name: "Samir Nasri",
  age: 28
})

const BenArfa = new Player({
	name: "Hatem Ben Arfa",
  age: 27,
  club: "Sevilla CF"
})

const Benz = new Player()
Nasri.introduce()
console.log("=========")
BenArfa.introduce()
console.log("=========")
Benz.introduce()