javascript - 为什么在使用 console.log 时 Javascript 中的参数会返回 [object Arguments]？

Question

我有以下功能

//simple function with parameters and variable
        function thirdfunction(a,b,c,d){
            console.log("the value of a is: " + a);
            console.log("the value of b is: " + b);
            console.log("the value of c is: " + c);
            console.log("the value of d is: " + d);
            console.log("the arguments for each values are: " + arguments);
            console.log("the number of arguments passed are: " + arguments.length);
        }

        console.log("no parameter values are passed");
        thirdfunction();

        console.log("only a and b parameter values are passed");
        thirdfunction(1,2);

但是，如果我连接文本 ，则当 arguments 中传递的值不显示时，每个值的参数是:。这是为什么？

连接时我从谷歌控制台得到的输出如下；

no parameter values are passed
the value of a is: undefined
the value of b is: undefined
the value of c is: undefined
the value of d is: undefined
the arguments for each values are: [object Arguments]
the number of arguments passed are: 0
only a and b parameter values are passed
the value of a is: 1
the value of b is: 2
the value of c is: undefined
the value of d is: undefined
the arguments for each values are: [object Arguments]
the number of arguments passed are: 2 

当我不连接时，会传递以下值。

no parameter values are passed
the value of a is: undefined
the value of b is: undefined
the value of c is: undefined
the value of d is: undefined
[]
the number of arguments passed are: 0
only a and b parameter values are passed
the value of a is: 1
the value of b is: 2
the value of c is: undefined
the value of d is: undefined
[1, 2]
the number of arguments passed are: 2 

编辑

不确定为什么这个问题被否决了，但我遇到的问题是当我使用语句 console.log("the arguments for each values are: "+ arguments); 中的输出控制台是 console.log("the arguments for each values are: "+ arguments); 但是如果我传递语句 console.log(arguments); 中的输出控制台是 [] 还是 [1, 2]?

Answer 1

编写 console.log("..."+ arguments) 它将强制将 arguments 转换为字符串。自 arguments is an object ，它的字符串表示是 [object Arguments]。如果您想要显示该对象的内容，请尝试在不连接的情况下传递它:

console.log("the arguments for each values are: ", arguments);