771. Jewels and Stones

You're given strings J representing the types of stones that are jewels, and S representing the stones you have. Each character in S is a type of stone you have. You want to know how many of the stones you have are also jewels.
The letters in J are guaranteed distinct, and all characters in J and S are letters. Letters are case sensitive, so "a" is considered a different type of stone from "A".

• Example 1:
  Input: J = "aA", S = "aAAbbbb"
  Output: 3

• Example 2:
  Input: J = "z", S = "ZZ"
  Output: 0

// method 1
var numJewelsInStones = function(J, S) {
    let splitJ = J.split('')
    let splitS = S.split('')
    let count = 0;
    for(let j = 0; j < splitJ.length; j++) 
    {
        for(let s = 0; s < splitS.length; s++)
        {
          if(splitJ[j] == splitS[s]) count++;
        }
    }
    return count;
};

// method 2
var numJewelsInStones = function(J, S) {
    let splitJ = J.split('')
    let splitS = S.split('')
    let count = 0;
    for(let j of splitJ) 
    {
        for(let s of splitS)
        {
          if(j == s) count++;
        }
    }
    return count;
};