JavaScript Count Duplicate Letter Recursively

Question

I face a problem while coding. I want to count how many letters in a word repeat recursively. My code looks like this :

var check = words[0]

  if(!words){
     return 0
  } else {
     for(var i = 0; i < words.length; i++){
        if(words[i] == check){
           return 1 //+ countDuplicate (words.slice(1))
        }
     }
     return countDuplicate (words.slice(1))
  }

example for test case :

countDuplicate ('greatestme') // 2, ==> which are 'e' 3 times and 't' 2 times

Answer 1

/* Method 1 */
function countDuplicate1(word) {
  var arr = word.split("").reduce((acc, cv) => {
    if(!acc[cv]) {
      acc[cv] = 1;
    } else {
      acc[cv]++;
    }
    return acc;
  }, {});
  return Object.values(arr).filter(val => val >1).length;
}

/* Method 2 */
function countDuplicate2(word) {
  var arr = [];
  for(var i=0; i< word.length; i++) {
    var chr = word[i];
    for(var j=i+1; j< word.length; j++) {
      if((word[j] == chr) && !arr.includes(word[j])) {
        arr.push(word[j]);
      }
    }
  }
  return arr.length;
}
var count1 = countDuplicate1('greatestme');
var count2 = countDuplicate2('greatestme');
console.log(count1);
console.log(count2);

See if this helps.