js 函数的保护函数 防止toString检测

let catvm = {};
(() => {
    "use strict";
    const $toString = Function.toString;
    const myFunction_toString_symbol = Symbol('('.concat('', ')_', (Math.random() + '').toString(36)));
    const myToString = function() {
        return typeof this == 'function' && this[myFunction_toString_symbol] || $toString.call(this);
    };
    function set_native(func, key, value) {
        Object.defineProperty(func, key, {
            "enumerable": false,
            "configurable": true,
            "writable": true,
            "value": value
        })
    };
    delete Function.prototype['toString']; //删除原型链上的toString
    set_native(Function.prototype, "toString", myToString); //自己定义个getter方法
    set_native(Function.prototype.toString, myFunction_toString_symbol, "function toString() { [native code] }"); //套个娃 保护一下我们定义的toString 否则就暴露了
    catvm.safefunction = (func) => {
        set_native(func, myFunction_toString_symbol, `function ${myFunction_toString_symbol,func.name || ''}() { [native code] }`);
    }; //导出函数到globalThis
}).call(this);


old_eval = eval;
eval = function(obj){
    if (obj.indexOf("new Date(); debugger; return") == -1){
        old_eval(obj)
    }else {
        return false;
    }
}

catvm.safefunction(eval);
console.log(eval.toString());