Freecodecamp: ES6: Use the Spread Operator to Evaluate Arrays In-Place

[FakeErFy]

Describe your problem and how to reproduce it:
In the challenge that I mentioned in the title there is an issue. Even when the output doesn't match with the challenge requirements but it still passes the challenge. I have linked some gifs so it is more understandable.

Add a Link to the page with the problem:
https://www.freecodecamp.org/learn/javascript-algorithms-and-data-structures/es6/use-the-spread-operator-to-evaluate-arrays-in-place

Tell us about your browser and operating system:

• Browser Name: Google Chrome
• Browser Version: 85.0.4183.121
• Operating System: Windows 10 64-bit

If possible, add a screenshot here (you can drag and drop, png, jpg, gif, etc. in this box):
The output doesn't match with the requirements but it still passes the challenge:
https://gyazo.com/f27f86327cd9dc9d5959c2dc456f1041

While this is the correct code and output:
https://gyazo.com/0d11507fed0226112f059f45c0e5b97f

This also passes the challenge:
https://gyazo.com/2e3ae5310e4b638b0156ffc174b2e155

[nhcarrigan]

Good catch!

The first test on this page uses:

assert(arr2.every((v, i) => v === arr1[i]));

A fun quirk with .every() that I ran in to yesterday is that it returns true on an empty array. This error could likely be fixed by adding an assertion for arr2.length.

[FakeErFy]

Good catch!

The first test on this page uses:

assert(arr2.every((v, i) => v === arr1[i]));

A fun quirk with .every() that I ran in to yesterday is that it _returns true_ on an empty array. This error could likely be fixed by adding an assertion for arr2.length.

Honestly I didn't know why it passed the challenge. Thank you for the explanation.

[RandellDawson]

Opening this up for contributions. As @nhcarrigan mentions, we just need an additional condition in the assert to test that arr2.length is non-zero (which means it would be truthy).

[misbagas]

you can find in stackovervlow