text: /**
   * @param {string} J
   * @param {string} S
   * @return {number}
   */
  const numJewelsInStones = (J, S) =>
    Array
      .from(S)
      .filter((x) => J.includes(x))
      .length;
  
  const main = () => {
    const J = 'aA';
    const S = 'aAAbbbb';
    const output = numJewelsInStones(J, S);
    console.log(output);
  };
  
  main();
  