Merge two strings with alternating letters: abc, xyz => axbycz

mergeTwoStrings.js

function mergeAlternately(word1, word2) {
  // get max length of each word
  let m = word1.length,
    n = word2.length,
    // starting word
    result = '';

  // if either index is less than word length, add current letter to result

  for (i = 0; i < Math.max(m, n); i++) {
    if (i < m) {
      result += word1[i];
    }
    if (i < n) {
      result += word2[i];
    }
  }
  return result;
}

mergeAlternately('abc', 'xyz');

mergeTwoStrings_revision.js

function mergeAlternately(word1, word2) {
  // get max length of each word
  let m = word1.length,
    n = word2.length,
    // starting word and indices
    result = '',
    i = 0,
    j = 0;

  // if either index is less than word length, 
  // add current letter to result then add to that index
  while (i < m || j < n) {
    if (i < m) {
      result += word1[i];
      i++;
    }
    if (j < n) {
      result += word2[j];
      j++;
    }
  }
  return result;
}

mergeAlternately('abc', 'xyz');

Leetcode 1768. Merge Strings Alternately

Thought process

1. Get length of each word and start two indexes at 0, set result string variable
2. While loop checks if either index is less, if so, add current letter (starting with first word) and move index forward
3. Return result