❗️Что будет на выходе:

const data = { a: 1, b: 2, c: 3 };
const { a, ...rest } = data;
const newObj = { ...rest, a, d: 4 };

const arr = [1, 2, 3, 4, 5];
const [first, , third, ...remaining] = arr;
const result = [...remaining, third, first];

console.log(newObj);
console.log(result);

Ответ: { b: 2, c: 3, a: 1, d: 4 } [4, 5, 3, 1]

JavaScript test | #JavaScript