proxy与define_property

time 6m25s

get set
time 10m43s

set代替了writeable

time 12m54s

time 15m58s

var obj = {
    get a() {
        return 5;
    },
    set a(val) {
        this.a = val;
    }
}
// obj.a=10;
/*RangeError: Maximum call stack size exceeded*/
console.log(obj.a);//5

var obj = {
    get a() {
        return 5;
    },
    set a(val) {
        this.a = val;
    }
}
obj.a=10;
/*RangeError: Maximum call stack size exceeded
* 执行set操作，set操作中继续调用set操作，无限循环*/
// console.log(obj.a);//5

time 19m
一般都这样写

var obj = {
    _a: 5,
    get a() {
        return this._a;
    },
    set a(val) {
        this._a = val;
    }
}
obj.a = 10;
console.log(obj.a);//10 设置成功

writeable等都是源操作，共有4种，多么，不多。

time 22m23s

    var obj = {};
    var _a = 5;
    Object.defineProperty(obj, "a", {
        get() {
            return _a;
        },
        set(val) {
            console.log(this);
            this._a=val;
            /*这样设置还是5,_a是外界的，不是内部的,相当于obj新建了一个_a*/
            // _a = val;
        }
    })
    obj.a = 10;
    console.log(obj.a);//5

    var obj = {};
    var _a = 5;
    Object.defineProperty(obj, "a", {
        get() {
            return _a;
        },
        set(val) {
            console.log(this);
            this._a=val;
            /*这样设置还是5,_a是外界的，不是内部的*/
            _a = val;
        }
    })
    obj.a = 10;
    console.log(obj.a);//10

time 26m10s

   var pipe = function (value) {
        var arr = [];
        var proxy = new Proxy(
            {},
            {
                get(target, property, receiver) {
                    if (property === 'get') {
                        // console.log(arr);
                        // arr.reduce((pre,item,index)=>{},value,)
                        return arr.reduce((val, fn) => {
                            return fn(val);
                        }, value)
                        return;
                    }
                    ;
                    arr.push(window[property]);
                    return receiver;
                }
            }
        );
        return proxy;
    };
    var double = n => n * 2;
    var pow = n => n * n;
    var reverseInt = n =>
        n
            .toString()
            .split("")
            .reverse()
            .join("");
    console.log(pipe(3).double.pow.reverseInt.get)

time 42m39

time 57m43s