Function def

06.Router/basic/js/vue.js:304–311

* Define a property. * * @param {Object} obj * @param {String} key * @param {*} val * @param {Boolean} [enumerable]

(obj, key, val, enumerable)

   */

  function def(obj, key, val, enumerable) {
    Object.defineProperty(obj, key, {
      value: val,
      enumerable: !!enumerable,
      writable: true,
      configurable: true
    });
  }

  /**
   * Debounce a function so it only gets called after the