arguments[0]()的詳解

var length = 10;
    
    function fn(){
        console.log(this.length);
    }

    var obj = {
        length:5,
        method:function(fn){
            fn();
            arguments[0]();
        }
    }

    obj.method(fn,1);

結果為10   2

arguments[0]() => fn() =>this指向arguments所以輸出arguments.length