Use the Rest Operator with Function Parameters var or const?

When i use var to declare ‘args’ the exercise passes, however if i use let or const it gives me an error.
I feel like i must be missing something from this lesson.

const sum = (function() {
    "use strict";
    return function sum(...args) {
      var args = [...args];
      return args.reduce((a, b) => a + b, 0);
  console.log(sum(1, 2, 3, 4)); // 6

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Link to the challenge:

I’ve edited your post for readability. When you enter a code block into the forum, precede it with a line of three backticks and follow it with a line of three backticks to make easier to read. See this post to find the backtick on your keyboard. The “preformatted text” tool in the editor (</>) will also add backticks around text.


You do not need to declare args, because you declared in as a parameter in your function already.