task-prototype2.js

/*
1. create prototype object
2. should itterate through object, aka forEach only for objects

obj.each(function(prop, val) {
  console.log( prop ); // name -> age
});
*/

Object.prototype.each = function(f) {
  for (var prop in this) {
    // iterate only through own property
    if (!this.hasOwnProperty(prop)) continue;

    var value = this[prop];
    f.call(this, prop, value);
  }
};

Object.defineProperty(Object.prototype, 'each', {
  enumerable: false
});

var obj = {
  name: 'Bobby',
  age: 25
};

obj.each(function(prop, val) {
  console.log( prop ); // name -> age
});