Javascript - deepEqual Comparison

Question

Question (From Eloquent Javascript 2nd Edition, Chapter 4, Exercise 4):

Write a function, deepEqual, that takes two values and returns true only if th

Answer 1

As you suspect, you're returning the match of the first property seen. You should return false if that property doesn't match, but keep looking otherwise.

Also, return false if there's no prop property found on y (that is, the counts match, but not the actual properties).

If all properties have matched, return true:

var deepEqual = function (x, y) {
  if (x === y) {
    return true;
  }
  else if ((typeof x == "object" && x != null) && (typeof y == "object" && y != null)) {
    if (Object.keys(x).length != Object.keys(y).length)
      return false;

    for (var prop in x) {
      if (y.hasOwnProperty(prop))
      {  
        if (! deepEqual(x[prop], y[prop]))
          return false;
      }
      else
        return false;
    }

    return true;
  }
  else 
    return false;
}

var deepEqual = function (x, y) {
  if (x === y) {
    return true;
  }
  else if ((typeof x == "object" && x != null) && (typeof y == "object" && y != null)) {
    if (Object.keys(x).length != Object.keys(y).length)
      return false;

    for (var prop in x) {
      if (y.hasOwnProperty(prop))
      {  
        if (! deepEqual(x[prop], y[prop]))
          return false;
      }
      else
        return false;
    }

    return true;
  }
  else 
    return false;
}

var obj = {here: {is: "an", other: "3"}, 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}));
// → false
console.log(deepEqual(obj, {here: {is: "an", other: "2"}, object: 2}));
// → false
console.log(deepEqual(obj, {here: {is: "an", other: "3"}, object: 2}));
// → true