Alphabetize a list by the nth character.js

/*
Description:
Write a function that accepts two parameters, i) a string (containing a list of words) and ii) an integer (n). The function should alphabetize the list based on the nth letter of each word.

The letters should be compared case-insensitive. If both letters are the same, order them normally (lexicographically), again, case-insensitive.

example:

function sortIt('bid, zag', 2) //=> 'zag, bid'
The length of all words provided in the list will be >= n. The format will be "x, x, x". In Haskell you'll get a list of Strings instead.
*/
function sortIt(list, n) {
    return list
    .split(', ')
    .sort((a, b) => {
      const charCodeA = a.toLowerCase().charCodeAt(n - 1)
      const charCodeB = b.toLowerCase().charCodeAt(n - 1)

      return charCodeA === charCodeB
        ? a.localeCompare(b)
        : charCodeA - charCodeB
    })
    .join(', ')
}