1.监听对象属性的操作（Es5）

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const obj = {
      name: "why",
      age: 18,
      height: 1.88
    }
 
    // 需求: 监听对象属性的所有操作
    // 监听属性的操作
    // 1.针对一个属性
    // let _name = obj.name
    // Object.defineProperty(obj, "name", {
    //   set: function(newValue) {
    //     console.log("监听: 给name设置了新的值:", newValue)
    //     _name = newValue
    //   },
    //   get: function() {
    //     console.log("监听: 获取name的值")
    //     return _name
    //   }
    // })
 
    // 2.监听所有的属性: 遍历所有的属性, 对每一个属性使用defineProperty
    const keys = Object.keys(obj)
    for (const key of keys) {
      let value = obj[key]
      Object.defineProperty(obj, key, {
        set: function(newValue) {
          console.log(`监听: 给${key}设置了新的值:`, newValue)
          value = newValue
        },
        get: function() {
          console.log(`监听: 获取${key}的值`)
          return value
        }
      })
    }
 
    // console.log(obj.name)
    // obj.name = "kobe"
    console.log(obj.age)
    obj.age = 17
    console.log(obj.age)
 
 
 
    // 什么是响应式?
    // const nameEl = document.querySelector(".name")
    // nameEl.textContent = obj.name
    // obj.name = "kobe"
    // obj.name = "james"

2.监听对象属性的操作（Es6）

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const obj = {
  name: "why",
  age: 18,
  height: 1.88
}
 
 
// 1.创建一个Proxy对象
const objProxy = new Proxy(obj, {
  set: function(target, key, newValue) {
    console.log(`监听: 监听${key}的设置值: `, newValue)
    target[key] = newValue
  },
  get: function(target, key) {
    console.log(`监听: 监听${key}的获取`)
    return target[key]
  }
})
 
// 2.对obj的所有操作, 应该去操作objProxy
// console.log(objProxy.name)
// objProxy.name = "kobe"
// console.log(objProxy.name)
// objProxy.name = "james"
 
objProxy.address = "广州市"
console.log(objProxy.address)

3.Proxy-其他捕获器的监听方法

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const obj = {
  name: "why",
  age: 18,
  height: 1.88
}
 
 
// 1.创建一个Proxy对象
const objProxy = new Proxy(obj, {
  set: function(target, key, newValue) {
    console.log(`监听: 监听${key}的设置值: `, newValue)
    target[key] = newValue
  },
  get: function(target, key) {
    console.log(`监听: 监听${key}的获取`)
    return target[key]
  },
 
  deleteProperty: function(target, key) {
    console.log(`监听: 监听删除${key}属性`)
    delete obj.name
  },
 
  has: function(target, key) {
    console.log(`监听: 监听in判断 ${key}属性`)
    return key in target
  }
})
 
delete objProxy.name
 
console.log("age" in objProxy)

4.Proxy-监听函数对象的操作

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function foo(num1, num2) {
  console.log(this, num1, num2)
}
 
const fooProxy = new Proxy(foo, {
  apply: function(target, thisArg, otherArgs) {
    console.log("监听执行了apply操作")
    target.apply(thisArg, otherArgs)
  },
  construct: function(target, otherArray) {
    console.log("监听执行了new操作")
    console.log(target, otherArray)
    return new target(...otherArray)
  }
})
 
// fooProxy.apply("abc", [111, 222])
new fooProxy("aaa", "bbb")

5.Reflect-和Object的区别之一

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"use strict"
 
const obj = {
  name: "why",
  age: 18
}
 
Object.defineProperty(obj, "name", {
  configurable: false
})
// Reflect.defineProperty()
 
// 1.用以前的方式进行操作
// delete obj.name
// if (obj.name) {
//   console.log("name没有删除成功")
// } else {
//   console.log("name删除成功")
// }
 
// 2.Reflect
if (Reflect.deleteProperty(obj, "name")) {
  console.log("name删除成功")
} else {
  console.log("name没有删除成功")
}

6.Reflect-和Proxy共同完成代理

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const obj = {
  name: "why",
  age: 18
}
 
const objProxy = new Proxy(obj, {
  set: function(target, key, newValue, receiver) {
    // target[key] = newValue
    // 1.好处一: 代理对象的目的: 不再直接操作原对象
    // 2.好处二: Reflect.set方法有返回Boolean值, 可以判断本次操作是否成功
    const isSuccess = Reflect.set(target, key, newValue)
 
    if (!isSuccess) {
      throw new Error(`set ${key} failure`)
    }
  },
  get: function(target, key, receiver) {
 
  }
})
 
// 操作代理对象
objProxy.name = "kobe"
console.log(obj)

7.Reflect-Reflect设置receiver

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const obj = {
  _name: "why",
  set name(newValue) {
    console.log("this:", this) // 默认是obj
    this._name = newValue
  },
  get name() {
    return this._name
  }
}
 
 
// obj.name = "aaaa"
 
// console.log(obj.name)
// obj.name = "kobe"
 
const objProxy = new Proxy(obj, {
  set: function(target, key, newValue, receiver) {
    // target[key] = newValue
    // 1.好处一: 代理对象的目的: 不再直接操作原对象
    // 2.好处二: Reflect.set方法有返回Boolean值, 可以判断本次操作是否成功
    /*
       3.好处三:
         > receiver就是外层Proxy对象
         > Reflect.set/get最后一个参数, 可以决定对象访问器setter/getter的this指向
    */
    console.log("proxy中设置方法被调用")
    const isSuccess = Reflect.set(target, key, newValue, receiver)
 
    if (!isSuccess) {
      throw new Error(`set ${key} failure`)
    }
  },
  get: function(target, key, receiver) {
    console.log("proxy中获取方法被调用")
    return Reflect.get(target, key, receiver)
  }
})
 
 
// 操作代理对象
objProxy.name = "kobe"
console.log(objProxy.name)

8.Reflect-和construct结合的反射

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function Person(name, age) {
  this.name = name
  this.age = age
}
 
function Student(name, age) {
  // Person.call(this, name, age)
  const _this = Reflect.construct(Person, [name, age], Student)
  return _this
}
 
// const stu = new Student("why", 18)
const stu = new Student("why", 18)
console.log(stu)
console.log(stu.__proto__ === Student.prototype)