Leetcode771. Jewels and Stones

/**
 * @param {string} J
 * @param {string} S
 * @return {number}
 */

var numJewelsInStones = function(J, S) {
    let splitJ = J.split("");
    let splitS = S.split("");
    let output = [];
    
    for(let i = 0; i < splitS.length; i++) {
        for(let j = 0; j < splitJ.length; j++) {
            if(splitS[i] === splitJ[j]) {
                output.push(splitS[j])
                break;
            }
        }
    }
    return output.length;
};