Length of the Longest Alphabetical Continuous Substring

var longestContinuousSubstring = function(s) {
let n = s.length, count = 1, ans = 1;
  for (let i = 1; i < n; i++) {
    let currCharcode = s.charCodeAt(i);
    let prevCharcode = s.charCodeAt(i - 1);
    if (currCharcode - prevCharcode === 1) count++;
    else count = 1;
    ans = Math.max(ans, count);
  }
  return ans;
};