const arr1 = Array.from({ length: 5 }).map(() =>
    Math.round(Math.random() * 100)
);
let arr2 = [];
for (let i = arr1.length - 1; i >= 0; i -= 1) {
    arr2.push(arr1[i]);
    arr2.unshift(arr1[i]);
}
console.log(arr1);
console.log(arr2);