Compare two arrays (intersection, difference)

compareArrays.js

const arr1 = ["100730651975","100727767835","100731535949","100734119022","100731395492","100730978223","100723043671","100729513754","100731428590","100730087084","100731202777","100730337035","100731122761","100730787720","100730178609","100734126093","100731453507","100730654591","100730236974","100734127056"];

const arr2 = ["100730178609", "100730654591", "100730651975", "100730087084", "100727767835", "100731535949", "100731395492", "100723043671", "100730978223", "100729513754", "100731202777", "100731428590", "100731122761", "100730787720", "100731453507", "100730236974", "100734127056"];

const compareArrays = (a, b) => {
    const setOfA = new Set(a);
    const setOfB = new Set(b);
    
    const intersection = new Set(); // elements in both A and B
    const differenceB = new Set(); // elements in B but not in A
    const differenceA = new Set(); // elements in A but not in B
    
    const length = Math.max(a.length, b.length);
    
    let elemOfA, elemOfB;
    Array.from(Array(length).keys()).forEach((index) => {
        elemOfA = a[index];
        elemOfB = b[index];
        
        if (elemOfA) {
            if (setOfB.has(elemOfA)) {
                intersection.add(elemOfA);
            } else {
                differenceA.add(elemOfA);
            }
        }
        
        if (elemOfB) {
            if (setOfA.has(elemOfB)) {
                intersection.add(elemOfB);
            } else {
                differenceB.add(elemOfB);
            }
        }
    });
    
    console.log('Intersection:', Array.from(intersection));
    console.log('Elements in B but not in A:', Array.from(differenceB));
    console.log('Elements in A but not in B:', Array.from(differenceA));
};

compareArrays(arr1, arr2);