code javascript: Replace all question marks in a given string to obtain a palindrome.

Task description

Write a function solution that, given a string S of length N$,$ returns any palindrome which can be obtained by replacing all of the question marks in S by lowercase letters $(\text{'}$a$\text{'}\text{'}$z$\text{'}).$ If no palindrome can be obtained, the function should return the string $"$NO$".$

A palindrome is a string that reads the same both forwards and backwards. Some examples of palindromes are: "kayak", "radar", "mom".

Examples:

$1.$ Given S $="?$ab$??$a$",$ the function should return "aabbaa".

$2.$ Given S $=$ "bab??a$",$ the function should return $"$NO$".$

$3.$ Given S $="?$a$?",$ the function may return "aaa". It may also return "zaz", among other possible answers.

Assume that:

$$ N is an integer within the range $[1.\mathrm{.}1,000]$;

$$ string S consists only of lowercases letters $(\text{'}$a$\text{'}\text{'}$z$\text{'})$ or $\text{'}?\text{'}.$

In your solution, focus on correctness. The performance of your solution will not be the focus of the assessment.