LeetCode > 1768. Merge Strings Alternatively (JavaScript solution)

leetcode-1768

/**
 * Merge Strings Alternatively
 *
 * @param {String} word1
 *   String of characters.
 *
 * @param {String} word2
 *  String of characters.
 *
 * @return {String}
 *
 * @see https://leetcode.com/problems/merge-strings-alternately/description/?envType=study-plan-v2&envId=leetcode-75
 */
const mergeAlternately = function(word1, word2) {
  word1 = word1.split('');
  word2 = word2.split('');

  const len = [...word1, ...word2].length;

  let str = '';

  for (let i = 0; i < len; i++) {
    str += (i % 2)
      ? word2.shift() || word1.shift()
      : word1.shift() || word2.shift();
  }

  return str;
};

mergeAlternately('abc', 'pqr'); // apbqcr
mergeAlternately('ab', 'pqrs'); // apbqrs
mergeAlternately('abcd', 'pq'); // apbqcd

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