Wsy this arrow function doesn't work with 'arguments.length'?

Question

I'm wondering why the following arrow function, named 'countArg2' doesn't work. Is there anybody can explain what's wrong please?

This works

function countArg1() {
    return arguments.length;
}
countArg1(1, 2, 3);   //3

This doesn't work..

const countArg2 = () => arguments.length;
countArg2(1, 2, 3);
 // VM6745:1 Uncaught ReferenceError: arguments is not defined

Thank you in advance.

https://stackoverflow.com/questions/41731854/why-do-arrow-functions-not-have-the-arguments-array — Shivam Pal, Jan 15 '21 at 10:14
Hi Suzuran: It's already answered here :) https://stackoverflow.com/questions/41731854/why-do-arrow-functions-not-have-the-arguments-array — Imran Rafiq Rather, Jan 15 '21 at 10:16
[Arrow function expressions - JavaScript | MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/Arrow_functions) -> Differences & Limitations -> _"Does not have `arguments`, or `new.target` keywords."_ — Andreas, Jan 15 '21 at 10:16

score 1 · Accepted Answer · answered Jan 15 '21 at 10:13

You have to parse the arguments to the arrow function like this

const countArg2 = (...arguments) => arguments.length;
console.log(countArg2(1, 2, 3));
 // VM6745:1 Uncaught ReferenceError: arguments is not defined
 // at mArgs (<anonymous>:1:29)
 // at <anonymous>:2:1

Wsy this arrow function doesn't work with 'arguments.length'?

1 Answers1