The Rest operator ...varName

The Rest operator usage

const sumUp = (a, b, ...numbers) => {
  let sum = a + b;
  for (const num of numbers) {
    sum += num;
  }
  return sum;
};

const subtractUp = function () {
  let sum = 0;
  for (const num of arguments) {
    sum -= num;
  }
  return sum;
};

console.log(`SumUp less ${sumUp(1, 5, 10, -3, 6, 10)}`);
console.log(`Sumup more args${sumUp(1, 5, 10, -3, 6, 10, 25, 88)}`);
console.log(`Subtract up ${subtractUp(1, 10, 15, 20)}`);