export function commonChars(a: string, b: string): number {
  // Escribe tu solución aquí
  if(!a.length || !b.length) return 0

  let totalCount = 0;

  for(let aChar of new Set([...a.toLowerCase()])){
    if(new Set([...b.toLowerCase()]).has(aChar)) totalCount += 1;
  }
  
  return totalCount;

}