4.3

// Your code here.
function deepEqual(obj1,obj2){
  if(obj1===obj2) return true;
  
 if (obj1 == null || typeof obj1 != "object" ||
      obj2 == null || typeof obj2 != "object")
    return false;
  
var propObj1 = 0, propObj2 = 0;

  for (var prop in obj1)
    propObj1 += 1;

  for (var prop in obj2) {
    propObj2 += 1;
    if (!(prop in obj1) || !deepEqual(obj1[prop], obj2[prop]))
      return false;
  }

  return propObj1 == propObj2;
}



var obj = {here: {is: "an"}, object: 2};
console.log(deepEqual(obj, obj));
// → true
console.log(deepEqual(obj, {here: 1, object: 2}));
// → false
console.log(deepEqual(obj, {here: {is: "an"}, object: 2}));
// → true