deepEqual

function deepEqual(first, second) {
  if (first === undefined && second === undefined)
    return true;
  if ([first, second].filter(item => item === undefined).length === 1)
    return false;

  let [firstType, secondType] = [typeof first, typeof second];

  if (firstType !== "object" && secondType !== "object")
    return first === second;

  let firstProps = first === null ? [] : Object.getOwnPropertyNames(first).sort();
  let secondProps = second === null ? [] : Object.getOwnPropertyNames(second).sort();

  if (firstProps.length !== secondProps.length)
    return false;

  for (i in firstProps)
    if (firstProps[i] !== secondProps[i])
      return false;

  for (i in firstProps) {
    let currentFirstProp = firstProps[i];
    if (!secondProps.includes(currentFirstProp) || !deepEqual(first[currentFirstProp], second[currentFirstProp]))
      return false;
  }

  return true;
}

function main() {
  let a = { location: [1, 1, 1], rotation: [0, 0, 0] }
  let b = { location: [1, 1, 1], rotation: [0, 0, 0] }

  console.log(deepEqual(null, a));
}