code: function isValidLatLng(elem) {
      return elem !== null && (typeof elem === 'undefined' ? 'undefined' : _typeof(elem)) === 'object' && elem.hasOwnProperty('lat') && elem.hasOwnProperty('lng');
    }
docs: Helper that checks whether an array consists of objects
  with lat and lng properties
  @param {object} elem the element to check
  @returns {boolean} whether or not it's valid