Number of deletions needed to make two random strings, anagrams of each other in Javascript

anagram.js

function anagrams(a, b) {
  var freqA = charFreq(a);
  var freqB = charFreq(b);
  var deletions = 0;
  
  getChars().forEach(char => {
  	deletions += Math.max(freqA[char], freqB[char]) - Math.min(freqA[char], freqB[char]);
  });
  
  return deletions;
}

function getChars() {
	return 'abcdefghijklmnopqrstuvwxyz'.split('');
}

function charFreq(str) {
  var chars = getChars();
  str = str.toLowerCase();
	var freq = {};
  chars.forEach(char => {
  	var charNum = str.split('').filter(x => x === char);
    freq[char] = charNum ? charNum.length : 0;
  });
  return freq;
}