浅析vue数据绑定

var a = {};&＃8232;
Object.defineProperty(a, "b", {&＃8232; 
 set: function (newValue) {&＃8232; 
 console.log("我被赋值了！" + newValue);&＃8232; 
 },&＃8232; 
 get: function () {&＃8232; 
 console.log("我被取值了！");&＃8232; 
 return 2 
 }&＃8232;})&＃8232;
a.b = 3; //我被赋值了！&＃8232;
console.log(a.b); //我被取值了! //打印 2

var data = {name: 'beidan'};&＃8232;
observe(data);&＃8232;
data.name = 'test'; // 监听到值变化了 beidan 变成 test&＃8232;&＃8232;function observe(data) {&＃8232; 
 if (!data || typeof data !== 'object') {&＃8232; 
 return;&＃8232; 
 }&＃8232; 
 // 取出所有属性遍历&＃8232; 
 Object.keys(data).forEach(function(key) {&＃8232; 
  defineReactive(data, key, data[key]);&＃8232;
 });
}

function defineReactive(data, key, val) {&＃8232;&＃8232;
 Object.defineProperty(data, key, {&＃8232;
 enumerable: true, // 可枚举&＃8232; 
  configurable: false, // 不能再define
  get: function() {&＃8232;  
   return val;&＃8232; 
  },&＃8232; 
  set: function(newVal) {&＃8232;  
   console.log('监听到值变化了 ', val, ' 变成 ', newVal);&＃8232;
   val = newVal;&＃8232; 
  }&＃8232; 
 });
}

function Dep() {&＃8232; 
 this.subs = [];
}
&＃8232;Dep.prototype = {&＃8232; 
 addSub: function (sub) {&＃8232; 
 this.subs.push(sub);&＃8232; 
 },&＃8232; 
 notify: function (val) {&＃8232; 
  this.subs.forEach(function (sub) {&＃8232;  
  sub.update(val)&＃8232; 
 });&＃8232; 
}&＃8232;};
function defineReactive(data, key, val) {
 Object.defineProperty(data, key, {
 ……
 set: function(newVal) {
  if (val === newVal) return;
  console.log('监听到值变化了 ', val, ' 变成 ', newVal);
  val = newVal;
  dep.notify(val); // 通知所有订阅者 
 } 
 });
}

bindText: function () {&＃8232; 
 var textDOMs = this.el.querySelectorAll('[v-text]'),&＃8232;bindText,_cOntext= this;&＃8232;&＃8232; 
 for (var i = 0; i