03. Characters in Range

function solve (firstChar, secondChar) {

    let charSort = [firstChar, secondChar].sort();

    function charArray() {
        let result = '';
        for (let i = charSort[0].charCodeAt(0) + 1; i < charSort[1].charCodeAt(0); i++) {
            result += String.fromCharCode(i) + ' ';
        }
        return result.trimEnd();
    }

    console.log(charArray());
}