Why is this anagram function not correct?

Question

Just got back my test for my Javascript class and I missed a question that I felt quite certain about.

We were supposed to make a function that returned true if two strings were anagrams, and false otherwise. I cant find an instance where this wouldn't work. I would appreciate any help!

This is what I had:

function isAnagram(str1, str2){
    if(str1.length !== str2.length){
        return false;
    }
    else{
        for(var i = 0; i < str1.length; i++){
            if(!str2.includes(str1[i])){
                return false;
            }
         }
         return true;
     }
}

Answer 1

It only checks that each letter of str1 is present in str2, regardless of how many times they appear.

EDIT: It also doesn't check if str2 has letters that don't appear in str1.

function isAnagram(str1, str2) {
  if (str1.length !== str2.length) {
    return false;
  } else {
    for (var i = 0; i < str1.length; i++) {
      if (!str2.includes(str1[i])) {
        return false;
      }
    }
    return true;
  }
}

console.log(isAnagram('hello', 'hlleo'), ', should be true'); // true: correct
console.log(isAnagram('bye', 'byee'), ', should be false'); // false: correct
console.log(isAnagram('byeb', 'byee'), ', should be false'); // true: incorrect
console.log(isAnagram('byeb', 'byte'), ', should be false'); // true: incorrect