Is Array.sort disabled?
Ps. Nah... I had it wrong.

Thanks!

Immutability is hip for a reason: not having side effects prevents bugs.

I'd argue that Array.prototype.sort's purpose is not returning a value; its purpose is sorting its argument in place ( probably for performance reasons ), and therefore should not return a value as well - it should have one effect and not two. People tend to use something.sort() directly and forget this also sorts something in place, often leading to bugs.

MDN "Enumerability and ownership of properties":

Enumerable properties are those properties whose internal enumerable flag is set to true, which is the default for properties created via simple assignment or via a property initializer. Properties defined via Object.defineProperty and such default enumerable to false.

Enumerable properties show up in for..in loops unless the property's key is a Symbol.

Testing sometimes uses for..in ( or equivalent ) instead of for..of ( or equivalent ), which leads to unexpected results when extending Array the wrong way ( it's legal, but for exactly this reason I'm actually calling it wrong ). I have been bitten by this ( because I'm lazy sometimes ).

Added.

And no, you're right to not assume it, because the default .sort method modify the original array.

without paying attention to enumerability is bugs all over the place just waiting to happen

Could you elaborate that part?

Just wondering, why shouldn't we modify the original array? Sort() method modifies the original array. After all, that's the purpose of this method - to return modified (sorted) array, right? Hence I assumed that our sortReloaded() method should mutate the original array as well.

• Node 12 should be enabled (Refer this and this for more info)

Still misunderstood what parameter it takes so it returns unmodified array?

I'd add in description that it should not modify the original array. I got to know it from the tests. Maybe I'm stupid that I didn't assume it, I'd add it though :D

It shouldn't sort the elements in-place.

I just got it, it says our method should return a new array

NaN is not a finite number. Closing.

Can someone explain in what condition our method should not modify an array? thanks.

Congratulations, the 1st step to a remarkable future