const numbers = [1, 2, 3, 4, 5];
const result = numbers
  .filter(n => n % 2 === 0)
  .map(n => n * 2)
  .reduce((acc, curr) => acc + curr, 0);

const original = numbers.slice();
numbers.splice(2, 1, 99);

console.log(result);
console.log(numbers);
console.log(original);