Proxy

var window = {key: "qww",age: 22
}
window = new Proxy(window, {get(target, p, receiver) {console.log("target: ", target);console.log("p: ", p);// return window['username'];/// 这里如果这样写. 有递归风险的...// return Reflect.get(...arguments);return Reflect.get(target, p);},set(target, p, value, receiver) {console.log("设置操作")Reflect.set(target, p, value);}
}); console.log(window.username);
console.log(window.age);
window.username = "qww_qww"
window.age = 18

function use_proxy(obj) {return new Proxy(obj, {get(target, p, receiver) {let val = Reflect.get(...arguments);console.log("<<==:", "get("+ p+ ")", "return_val=" + val, target);return val;},set(target, p, value, receiver) {console.log("==>>: ",  p +".set("+ value +")", target);return Reflect.set(...arguments);}});
}// 
window = use_proxy(window)

Hook

function foo(a, b, c, d, e, f) {console.log("foo功能...")console.log(a, b, c, d, e, f)return 123
}var _foo = foofoo = function () {console.log("begin hook")// _foo(arguments)_foo.apply(this,arguments)console.log("end Hook")
}foo(1,2,3,4,5,6,7)

Trace

const traceProperty = (object, property) => {let value = object[property];Object.defineProperty(object, property, {get() {console.trace(`${property} requested`);return value;},set(newValue) {console.trace(`setting ${property} to `, newValue);value = newValue;}});
};//var foo = {name: '张三',
};Object.defineProperty(foo, 'age', {get: function () {console.log('==>> get');return count;},set: function (val) {console.log('==>> set ');count = val + 1;},
});foo.age = 18;
console.log(foo.age);