Given a string str and a set of words dict, find the longest word in dict that is a subsequence of str.

longestWord.js

// function to determine if a word is subsequence to another
const isSubsequence = (s, t) => {
    let i = 0, j = 0;
    while (i < s.length && j < t.length) {
        if (s[i] === t[j]) {
            i++;
        }
        j++;
    }
    return i === s.length
};

const longestWord = (str, dict) => {
  let longest = 0, result = '';
  for (let word of dict) {
    if (isSubsequence(word, str) && word.length > longest) {
      longest = word.length;
      result = word;
    }
  }
  return result
}

// longestWord("abppplee", ["able", "ale", "apple", "bale", "kangaroo"]) --> "apple"