Exercicio - transformar string

excercicio.txt

Transformar uma string em outra na qual cada letra do alfabeto deve ser a proxima mantendo o resto igual. ex: a -> b, z -> a, f -> g.
Após a transformação gerar uma nova string onde toda vogal deve ser maiúscula.

exemplos:

Input:"hello*3"

Output:"Ifmmp*3"

Input:"fun times!"

Output:"gvO Ujnft!"

transform.js

const stringToArray = string => string.split("");
const ALPHABET = [...Array(26).keys()].map(pre => String.fromCharCode(97 + pre));
const findCharIndex = letter => ALPHABET.indexOf(letter);
const verifyLastCharIndex = char => findCharIndex(char) + 1 > ALPHABET.length - 1
    ? 0
    : findCharIndex(char) + 1;
const toString = list => list.join("");
const getChar = char => findCharIndex(char) >= 0
    ? ALPHABET[verifyLastCharIndex(char)]
    : char;

const resolve = string => {

    const newStringArray = stringToArray(string)
        .map(getChar);
    const newString = toString(newStringArray);
    const upperVowels = newString.replace(/[aeiou]/g, (char) => char.toUpperCase());
    const result = upperVowels;

    return result;

};

console.log(resolve("hello*3")); //Ifmmp*3
console.log(resolve("fun times!")); //gvO Ujnft!

const ALPHABET = [ ...Array(26).keys() ].map( pre => String.fromCharCode( 97 + pre ) );
const stringToArray = string => string.split("");
const findCharIndex = letter => ALPHABET.indexOf(letter);
const toString = list => list.join("");
const mapTo = arr => arr.map( toAlphabet( ALPHABET ) );

const verifyLastCharIndex = char => 
  findCharIndex(char) + 1 > ALPHABET.length - 1
    ? 0
    : findCharIndex(char) + 1;

const toAlphabet = ALPHABET => char => 
  ( findCharIndex( char ) >= 0 )
    ? ALPHABET[verifyLastCharIndex(char)]
    : char

const transformToUpperCase = newString => 
  newString.replace( /[aeiou]/g, char => char.toUpperCase() );

const result = string => 
  transformToUpperCase( toString( mapTo( stringToArray( string ) ) ) );


console.log(result("hello*3"));
console.log(result("fun times!"));