还是函数劫持。。

            var fn = function(a, b, c) {
                return a + b + c;
            }
            var args = createArgumentsString(fn.length)

            function createArgumentsString(arity) {
                var str = ‘‘

                for(var i = 0; i < arity; i++) {
                    str += ‘, arg‘ + i
                }

                return str.substr(2)
            }
            console.log(args);
            var deprecatedfn = eval(‘(function (‘ + args + ‘) {\n‘ +
                ‘"use strict"\n‘ +
                ‘return fn.apply(this, arguments)\n‘ +
                ‘})‘)
            console.log(deprecatedfn(1,5,3));