code: function recurPath(obj, arr, lastKey = '') {
    if (arr.length === 0) {
      return { [lastKey]: obj };
    } else {
      return recurPath(obj[arr[0]], arr.slice(1), arr[0]);
    }
  }
docs: /* Object, Array-of-String -> Object
  retrieves the value of an object at the given path
  returns { String-X: object }
  where String-X is the key from the last index of
  the given array