const intersect = function (arr1, arr2) {
    let set = new Set();
    let res = [];

    for (let i = 0; i < arr1.length; i++) {
        if (!set.has(arr1[i])) {
            set.add(arr1[i]);
        }
    }

    for (let j = 0; j < arr2.length; j++) {
        if (set.has(arr2[j])) {
            res.push(arr2[j])
        }
    }

    return res;
}