var numbers = [3, 5, 7, 2];
var sum = numbers.reduce((x, y) => x + y);
console.log(sum); // returns 17

// other way

x = sumAll(1, 123, 500, 115, 44, 88);

function sumAll() {
  var i;
  var sum = 0;
  for (i = 0; i < arguments.length; i++) {
    sum += arguments[i];
  }
  return sum;
}

// define a list
const list = [1,2,3,4,5];

// create a function return result of sum of elements
const result = () => {
  let sum = 0;
  for (let i = 0; i < list.length; i++) {
    sum += list[i];
  }
  return sum
}
console.log(result());