Final Exam 02. Song Encryption alternative

function solve(input) {

  for (const line of input) {
    if (line === 'end') {
      break;
    }

    let [ artist, song ] = line.split(':');

    if (!/^[A-Z][a-z\s\']+$/g.test(artist) || !/^[A-Z\s]+$/g.test(song)) {
     console.log('Invalid input!');
     continue;
   }

   let key = artist.length;
   let encryptedString = '';
   for (const char of line) {
     if (char === ':') {
       encryptedString += '@';
       continue;
     }

     let asciiCode = char.charCodeAt(0);
     if ((asciiCode >= 65 && asciiCode <= 90)) {
       asciiCode += key;
       if (asciiCode > 90) {
         asciiCode -= 26;
       }
     }

     if ((asciiCode >= 97 && asciiCode <= 122)) {
       asciiCode += key;
       if (asciiCode > 122) {
         asciiCode -= 26;
       }
     }

     encryptedString += String.fromCharCode(asciiCode);
   }

   console.log(`Successful encryption: ${encryptedString}`);
 }
}

// solve(
// [
//   'Eminem:VENOM',
//   'Linkin park:NUMB',
//   'Drake:NONSTOP',
//   'Adele:ROLLING IN THE DEEP',
//   'end'
// ]
// );

// solve([
//   'Michael Jackson:ANOTHER PART OF ME',
//   'Adele:ONE AND ONLY',
//   'Guns n\'roses:NOVEMBER RAIN',
//   'Christina Aguilera: HuRt',
//   'end'
// ])