Anagram difference.js

/*
Description:
Given two words, how many letters do you have to remove from them to make them anagrams?
Example
First word : c od e w ar s (4 letters removed)
Second word : ha c k er r a nk (6 letters removed)
Result : 10
Hints
A word is an anagram of another word if they have the same letters (usually in a different order).
Do not worry about case. All inputs will be lowercase.
When you're done with this kata, check out its big brother/sister : https://www.codewars.com/kata/hardcore-anagram-difference
*/
function anagramDifference(str1,str2){
    let count1 = Array(26).fill(0) 
    let count2 = Array(26).fill(0) 
    let i = 0
    while (i < str1.length){
        count1[str1[i].charCodeAt()-97] += 1
        i += 1
        }
    i =0
    while (i < str2.length){
        count2[str2[i].charCodeAt()-97] += 1
        i += 1
        }
   let result = 0
    for (let i = 0; i<26;i++){
        result += Math.abs(count1[i] - count2[i]) 
    }
    return result 
}