export function commonChars(a: string, b: string): number {
  // Escribe tu solución aquí
  const count = [];
  const setA = new Set(a.toLocaleLowerCase());
  const setB = new Set(b.toLocaleLowerCase());

  for (const char of setA) {
    if (setB.has(char)) count.push(char);
  }
  
  return count.length;
}