Simple Version of Valid Anagram O(n) Time Complexity

SimpleValidAnagram.js

/* Simple b/c it doesn't account for spaces, special chars etc...*/

const validAnagram = (str1, str2) => {
  // Immediately return if strings are diff length
  if (str1.length !== str2.length) return false;

  // Create "bank" for letters to live in
  let chars = {};

  // Loop over first string and add letters to chars
  for (let letter of str1) {
    // Add in each letter to the store of chars
    chars[letter] = (chars[letter] || 0) + 1;
  }

  // Loop over 2nd string
  for (let letter of str2) {
    // No matching letter -> falsy
    if (!chars[letter]) return false;
    // Matching letter gets reduced by one
    else chars[letter] -= 1;
  }

  // No falsy returns then it is a valid anagram
  return true;
};

// Simple Test Cases
console.log(validAnagram("", ""));
console.log(validAnagram("aaz", "zza"));
console.log(validAnagram("anagram", "nagaram"));
console.log(validAnagram("rat", "car"));
console.log(validAnagram("awesome", "awesom"));
console.log(validAnagram("qwerty", "qeywrt"));
console.log(validAnagram("texttwisttime", "timetwisttext"));