// vue 2.5.0
var arrayProto = Array.prototype;
var arrayMethods = Object.create(arrayProto); // Array {}
function def(obj, key, val, enumerable) {
  Object.defineProperty(obj, key, {
   value: val,
   enumerable: !!enumerable,
   writable: true,
   configurable: true
  });
}
var methodsToPatch = [
  'push',
  'pop',
  'shift',
  'unshift',
  'splice',
  'sort',
  'reverse'
  ];

  /**
  * Intercept mutating methods and emit events
  */
  methodsToPatch.forEach(function(method) {
  // cache original method
  var original = arrayProto[method]; 
    // 比如 method是push，则结果为
    // "htmlcode">

  let proxy = new Proxy(fruit, {
    get: function (obj, prop) {
      return prop in obj "newVal", newVal) // 输出{ name: "lemon", num: 999 }
      return true;
    }
  })
  proxy.push({ name: "lemon", num: 999 })
  console.log(fruit)





Proxy代理可以劫持对象的改变，defineProperty需要遍历


defineProperty




   let fruit = {
     "apple": 2,
     "pear": 22,
     "peach": 222
  }
  Object.keys(fruit).forEach(function (key) {
      Object.defineProperty(fruit[i], key, {
        enumerable: true,
        configurable: true,
        get: function () {
          return val;

        },
        set: function (newVal) {
          val = newVal; // 输出 newVal 888
          console.log("newVal", newVal)
        }
      })
    })
   fruit.apple = 888




Proxy




   let fruit = {
     "apple": 2,
     "pear": 22,
     "peach": 222
  }
  let proxy = new Proxy(fruit, {
    get: function (obj, prop) {
      return prop in obj "newVal", newVal) // 输出 newVal 888
      return true;
    }
  })
  proxy.apple = 888




Proxy代理可以劫持对象属性的添加，defineProperty用this.$set来实现

defineProperty，如果属性不存在，则需要借助this.$set




<div id="app">
  <span v-for="(value,name) in fruit">{{name}}:{{value}}个 </span> 
  <button @click="add()">添加柠檬</button>
</div>
<script src="/UploadFiles/2021-04-02/vue">



  Object.keys(fruit).forEach(function (key) {
    Object.defineProperty(fruit, key, {
      enumerable: true,
      configurable: true,
      get: function () {
        return val;

      },
      set: function (newVal) {
        val = newVal;
        console.log("newVal", newVal) // 根本没有进去这里
      }
    })
  })




Proxy 直接可以添加属性




// vue 3
<div id="app">
  <span v-for="(value,name) in fruit">{{name}}:{{value}}个 </span>
  <button @click="add()">添加柠檬</button>
</div>
<script src="/UploadFiles/2021-04-02/vue@next">



  let proxy = new Proxy(fruit, {
    get: function (obj, prop) {
      return prop in obj "newVal", newVal) // lemon, 888
      return true;
    }
  })
  proxy.lemon = 888




Proxy


其他属性

应用场景 promisify化


用Proxy写一个场景，请求都是通过回调，如果我们需要用promise包一层的话，则可以




// server.js
// 假设这里都是回调
export const searchResultList = function (data, callback, errorCallback) {
 axios.post(url, data, callback, errorCallback)
}





// promisify.js
import * as server from './server.js'
const promisify = (name,obj) => (option) => {
 return new Promise((resolve, reject) => {
  return obj[name](
   option,
   resolve,
   reject,
  )
 })
}
const serverPromisify = new Proxy(server, {
 get (target,prop) {
  return promisify(prop, server)
 }
})
export default serverPromisify




使用




// index.js
import serverPromisify from './serverPromisify'
serverPromisify.searchResultList(data).then(res=>{

})




如有不正确，望请指出

留下一个疑问，既然兼容性不是很好，那么尤大是怎么处理polyfill呢
 到此这篇关于vue中defineProperty和Proxy的区别详解的文章就介绍到这了,更多相关vue defineProperty和Proxy内容请搜索以前的文章或继续浏览下面的相关文章希望大家以后多多支持！



                                
                                

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