code: function hasValidLocation (otpState, locationKey) {
    return otpState.currentQuery[locationKey] &&
      otpState.currentQuery[locationKey].lat &&
      otpState.currentQuery[locationKey].lon
  }
docs: Determine if the current query has a valid location, including lat/lon
  @param {Object} otpState the OTP state object
  @param {string} locationKey the location key ('from' or 'to')
  @returns {boolean}