Proxy中代理数据拦截的方法详解

new Proxy(target,handler)

// target 是proxy 要包装的对象 （可以是数组、函数，也可以是另一个Proxy）
//handler 一个通常以函数作为属性的对象，用来定制拦截行为

const p = new Proxy(target,handler)

const obj = {
    name: '微芒不朽',
    occupation: '前端开发'
}

const handler = {
    has(target, key) {
        //判断是否存在该属性
        return key in target
    }
}


const p = new Proxy(obj, handler)
console.log(p.name) //微芒不朽
console.log(p.like) //undefined
console.log(p.occupation) //前端开发

const obj = {
    name: '微芒不朽',
    occupation: '前端开发'
}

const handler = {
    has(target, key) {
        //判断是否存在该属性
        return key in target
    },
    get(target, key) {
        if (key in target) {
            return target[key]
        } else {
            return new ReferenceError(key + '属性不存在')
        }
    }
}

const p = new Proxy(obj, handler)
console.log(p.name) //微芒不朽
console.log(p.like) //ReferenceError: like属性不存在
console.log(p.occupation) //前端开发

const obj = {
    name: '微芒不朽',
    occupation: '前端开发'
}

const handler = {
    set(target, key) {
        if (key in target) {
            return Reflect.set(...arguments)
        }
        throw new ReferenceError(key+'属性不存在')
    }
}

const p = new Proxy(obj, handler)
p.like = '编程' //Uncaught ReferenceError: like属性不存在
// console.log(p.like)
p.occupation = '测试'
console.log(p.occupation) //测试

const obj = {
    name: '微芒不朽',
    configurable: true,
    enumerable: true,
}

const handler = {
    defineProperty(target, key, descriptor) {
        console.log('属性', key)
        return true;
    }
}

const p = new Proxy({}, handler)
Object.defineProperty(p, 'like', obj) //属性 like

const obj = {
    name: '微芒不朽',
    configurable: true,
    enumerable: true,
}

const handler1 = {
    defineProperty(target, key, descriptor) {
        console.log('属性1', descriptor)
        return Reflect.defineProperty(target, key, descriptor)
    }
}

const p1 = new Proxy({}, handler)
Object.defineProperty(p1, 'like', obj) //属性 like

const obj = {
    name: '微芒不朽',
}

const handler = {
    deleteProperty(target, key) {
        console.log('删除' + key)
    }
}

const p = new Proxy({}, handler)
delete p.name //删除name

//也会拦截 Reflect.deleteProperty
Reflect.deleteProperty(obj,'name')

const obj = {
    name: '微芒不朽',
}
const handler = {}
const { proxy, revoke } = Proxy.revocable(obj, handler)
console.log(proxy.name) //微芒不朽
revoke() // 取值完成对proxy进行封闭，撤消代理
console.log(proxy.name) // Uncaught TypeError: illegal operation attempted on a revoked proxy

const obj = {
    certno: '420101198101012964',
    name: '微芒不朽1',
    tel: '123456789',
    mail: '13@qq.com',
}

const validators = {
    //校验证件号码
    certno(val) {
        return /(^\d{15}$)|(^\d{18}$)|(^\d{17}(\d|X|x)$)/.test(val)
    },
    //校验姓名，只能为汉字
    name(val) {
        return /^[\u0391-\uFFE5]+$/.test(val)
    },
    //检验电话或手机号
    tel(val) {
        return /^1\d{10}$|^0\d{2,3}-?\d{7,8}$/.test(val)
    },
    //检验邮箱
    mail() {
        return /^[a-zA-Z0-9_.-]+@[a-zA-Z0-9-]+(\.[a-zA-Z0-9-]+)*\.[a-zA-Z0-9]{2,6}$/.test(val)
    }
}

const validatorType = (target, validator) => {
   return new Proxy(target, {
        _validator: validator,
        set(target, key, value, proxy) {
            let validator = this._validator[key](value)
            if (validator) {
                return Reflect.set(target, key, value, proxy)
            } else {
                throw Error(`设置${key} 的值为 ${value}，格式不正确`)
            }
        }
    })
}

const proxy = validatorType(obj, validators)
proxy.certno = '420101198101012964'
proxy.name = '微芒不朽1' //Uncaught Error: 设置name 的值为 微芒不朽1，格式不正确
proxy.tel = '123456789' //Uncaught Error: 设置tel 的值为 123456789，格式不正确
proxy.mail = '13@qq.com'

let obj = {
    _id:'1234567890',
    name:'微芒不朽'
}
const p = new Proxy(obj,{
    set(target,prop){
        if(prop[0]==='_'){
            throw Error( `${prop}为私有属性`)
        }
        return Reflect.set(target,prop)
    }
})

p.name = '加油啊'
console.log(p.name) //加油啊
p._id = '123'
console.log(p._id) //Uncaught Error: _id为私有属性

//判断是否为对象
function isObject(value) {
    return value != null && (typeof value === 'object' || typeof value === 'function')
}

function reactive(obj) {
    if (!isObject(obj)) {
        return obj
    }
    return new Proxy(obj, {
        get(target, key) {
            // TODO:收集依赖
            return Reflect.get(target, key)
        },
        set(target, key, value) {
            // TODO:触发依赖
            return Reflect.set(target, key, value)
        }
    })
}
const state = reactive({
    name: '微芒不朽'
})
console.log(state) //Proxy代理的对象
// Proxy { <target>: {…}, <handler>: {…} }
// <target>: Object { name: "微芒不朽" }
// name: "微芒不朽"
// <prototype>: Object { … }
// <handler>: Object { get: get(target, key), set: set(target, key, value)
//  }
// get: function get(target, key)
// set: function set(target, key, value)