apply method example

apply_method.js

var incAge = function incAge(incValue) {
  return this.age + incValue;
}

var BirthDayBoy = function BirthDayBoy(){
  this.age = 12;
};

var boy = new BirthDayBoy();

var finalAge = incAge.apply(boy, [1]);
console.log(finalAge);