Function isReserved

06.Router/basic/js/vue.js:103–106

* Check if a string starts with $ or _ * * @param {String} str * @return {Boolean}

(str)

   */

  function isReserved(str) {
    var c = (str + '').charCodeAt(0);
    return c === 0x24 || c === 0x5F;
  }

  /**
   * Guard text output, make sure undefined outputs