I was so close to this before I just decided to use a loop, genuinely agonizing.

Actually, your solution is DRY in the runtime sense but the solution above is actually more DRY in terms of code since you don't have to repeat certain things.

lol

which is why this is predominantly voted a clever solution

You run N times d === 'R' you can DRY

ah ha Thanks !

I meant, arrow function doesn't need return. Read this: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/Arrow_functions

but this solution didn't use 'return'

No.

does arrow function no need 'return'?

Yes! Copy the array first (e.g., Array.prototype.slice or [...array]), then you can mutate it as much as you want.

np. ;)

You may find some bits of information here: https://github.com/codewars/codewars.com/wiki

Sorry, I am still learning how to use the site properly. Will need to look into guidelines more.

this is mutating the input. Bad practice...