diff two objects and return values/path which are different, null if there is no diff.

object-diff.js

function diffObjects(x, y) {
  if (x === y)               return null;
  if (x !== x)               return y !== y ? null : y;
  if (typeof x !== typeof y) return y;
  if (typeof x !== 'object') return y;
  var typeX = getType(x);
  var typeY = getType(y);
  if (typeX !== typeY)       return y;
  if (typeX === 'date'  )    return +x === +y ? null : y;
  if (typeX === 'array' )    return deepDiffArray(x, y);
  if (typeX === 'object')    return deepDiffObjects(x, y);
  return y;
}

function deepDiffArray(x, y) {
  return x.find((xx, i) => diffObjects(xx, y[i]) !== null) || null;
}

function getType(x) {
  var type = Object.prototype.toString.call(x);
  return type.substring(8, type.length - 1 ).toLowerCase();
}

function deepDiffObjects(x, y) {
  var keysX = Object.keys(x);
  var keysY = Object.keys(y);
  const diff1 = deepDiffArray(keysX.sort(), keysY.sort());
	return diff1 ? diff1 : deepCompareObjects(x, y);
}                      

function deepCompareObjects(x, y) {
	var keysX = Object.keys(x);
	const diff = keysX.find(k =>  {
		return diffObjects(x[k], y[k]) !== null;
	});
  return diff ? diff + '.' + diffObjects(x[diff], y[diff]) : null;
}

var actual = {
	foo: 'nar',
	nested: { 
   thing: {
    foobarbaz: 'stu5ff',
  },
   bar:  {
     biz: '111'
   }
  },
};

var requiredProps = {
  foo: 'nar',
  nested: {
    thing: {
     foobar: 'stuff',
   },
    bar:  {
      biz: '111'
    }
  },
};

console.log(deepDiffObjects(actual, requiredProps));