let numbers = [1, 2, 3, 4, 5]

let result = 0;

for (let i = 0, total = numbers.length; i < total; i = i + 1) {
  result = result + numbers[i];
}

let numbers = [1, 2, 3, 4, 5];

let result = numbers.reduce((acc, val) => acc + val, 0);