class Vue {
  constructor(option) {
    this._data = option.data
    this.obvers();
  }
  obvers() {
    const data = this._data;
    if (!data || typeof data != 'object') return false
    for (const key in data) {
      if (data.hasOwnProperty(key)) {
        this.definepro(data, key, data[key])
      }
    }
  }
  definepro(obj, key, value) {
    const _this = this;
    Object.defineProperty(obj, key, {
      enumerable: true,
      configurable: true,
      get() {
        return value
      },
      set(newval) {
        _this.change(value, newval)
      }
    })
  }
  change(value, newval) {
    console.log(`我把${value}跟新为${newval}`)
  }
}
var vue = new Vue({
  data: {
    name: 'lyh'
  }
})
vue._data.name = 1;