ES6（十一）Proxy和Reflect

Proxy

let obj = {
  time: ‘2019-01-01‘,
  name: ‘ronle‘
}
let monitor = new Proxy(obj, {
  // 拦截对象属性的读取
  get (target, key) {
    return target[key].replace(‘2019‘, ‘2020‘)
  },
  // 拦截对象设置属性
  set (target, key, value) {
    // 只有key等于name才修改
    if (key === ‘name‘) {
      return Reflect.set(target, key, value)
    } else {
      return target[key]
    }
  },
  // 拦截 key in object操作
  has (target, key) {
    if (key === ‘name‘) {
      return target[key]
    } else {
      return false
    }
  },
  // 拦截delete
  deleteProperty (target, key) {
    if (key.indexOf(‘-‘)) {
      delete target[key]
      return true
    } else {
      return target[key]
    }
  },
  // 拦截Object.keys
  // Object.getOwnPropertySymbols
  // Object.getOwnPropertyNames
  ownKeys (target) {
    return Object.keys(target).filter(item => item !== ‘time‘)
  }
})
// 2020-01-01
console.log(‘get‘, monitor.time)
monitor.time = ‘2030‘
monitor.name = ‘kaka‘
// 只有name被修改  kaka
console.log(‘set‘, monitor, monitor.name)

console.log(‘has‘, ‘name‘ in monitor, ‘time‘ in monitor)
// // 删除掉日期
// delete monitor.time
// console.log(‘delete‘, monitor)

// 返回不等于key不等于time的元素
console.log(‘ownKeys‘, Object.keys(monitor))


Reflect 跟proxy代理类似，方法属性都一样

let obj = {
  time: ‘2019-01-01‘,
  name: ‘ronle‘
}

console.log(Reflect.get(obj, ‘time‘))
Reflect.set(obj, ‘name‘, ‘kaka‘)
console.log(obj)
console.log(Reflect.has(obj, ‘name‘))