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console 命令行工具 X clear

                    
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console
// 利用 Proxy 包裹对象,使其读取不存在的变量时,不会报错,并返回 undefined ,设置变量的时候,能够自动设置其中不存在的值。
// 可选链,lodash的get
// Proxy / Reflect 

const a = {}

let windowProxy = window.Proxy

const Proxy = (obj) => {
    console.log(`Proxy${obj}`)
    return new windowProxy(obj, {
        get: function (target, propKey, receiver) {
            console.log(`getting ${propKey}!`);
            // console.log(target[propKey])
            console.log()
            if(!target[propKey]) {
                let temp = Proxy({})
            }
            
            if(!target[propKey]) return {}
            // try {
                
            // } catch {
            return Reflect.get(target, propKey, receiver);
            // }                
        },
        set: function (target, propKey, value, receiver) {
            console.log(`setting ${propKey}!`);
            return Reflect.set(target, propKey, value, receiver);
        }
    });
}

const b = Proxy(a)

console.log(b.a.c)
// const c = b.a
// console.log('=====', c)
// b.a.c.s // undefined
// b.a.c.bc = 1 // 不会报错