anagram removals

anagram-removals.js

/*
  Given two strings,  and , that may or may not be of the same length, determine the minimum number of character deletions required to make  and  anagrams. Any characters can be deleted from either of the strings.
  https://www.hackerrank.com/challenges/ctci-making-anagrams
*/

function indexChars(map, char) {
    if(!map.hasOwnProperty(char)) {
        map[char] = 0;
    }
    map[char]++;
    return map;
}

function findRemovals(mapA, mapB) {
    let removals = 0;

    for(let key in mapA) {
        let diff = Math.abs((mapA[key] || 0) - (mapB[key] || 0));
        removals += diff;
        if(diff > 0) {
            delete mapB[key];
        }
    }

    return removals;
}

function anagram(strA, strB) {
    let mapA = strA.split('').reduce(indexChars, {});
    let mapB = strB.split('').reduce(indexChars, {});

    let removals = 0;

    removals += findRemovals(mapA, mapB);
    removals += findRemovals(mapB, mapA);

    return removals;
}

console.log(anagram('cde', 'abc'));
console.log(anagram('fcrxzwscanmligyxyvym', 'jxwtrhvujlmrpdoqbisbwhmgpmeoke')); //30