From cassidoo's August 14, 2023 newsletter

faultyKeeb.ts

function faultyKeeb(str: string): string {
  const out = [];
  const vowels = ["a", "e", "i", "o", "u"];
  for (const ch of str) {
    if (vowels.includes(ch)) {
      out.reverse();
    } else {
      out.push(ch);
    }
  }
  return out.join("");
}

console.log(faultyKeeb("string"));
console.log(faultyKeeb("hello world!"));