return sum of an array code example

Example 1: how to add up all numbers in an array

var numbers = [10, 20, 30, 40] 
var sum = 0;
for (var i = 0; i < numbers.length; i++) {  sum += numbers[i]}

Example 2: sum the all values from an array

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;
}

Example 3: sum of an array

const sum = (...args) => args.reduce((a, b) => a + b, 0);
console.log(sum(1,2,3)); // returns 6