Return the longest sequence of consecutive characters in string

find-longest-sequence.js

// runner (s: string)
// return -- expects: Object { maxChar: numberOfOccurances }
const runner = (s="") => {
  let stringLength = (s.length - 1);
  let position = 0;
  
  let currentChar = "";
  let maxCount = 0;
  let count = 0;
  let maxChar = null;
  let prevChar = null;

  while(position < stringLength) {
    currentChar = s[position];
    // if prev character and current character are same, increment
    // otherwise set the count to 1
    if (prevChar == currentChar) {
      count += 1;
    } else {
      count = 1;
    }
    // if our current count is greatst, then it is now the largest count
    if (count > maxCount) {
      maxCount = count;
      maxChar = currentChar;
    }
    prevChar = currentChar;
    position++;
  }
  // because we expect an object to be returned
  // set it up as such
  let dict = {};
  dict[maxChar] = maxCount;
  return dict;  
}

let maxCharInString = runner("AABCDDBBBEA");
// will return { B: 3 }
console.log(maxCharInString);