how to add all values of array together js

1console.log(
2  [1, 2, 3, 4].reduce((a, b) => a + b, 0)
3)
4console.log(
5  [].reduce((a, b) => a + b, 0)
6)

1const sum = arr => arr.reduce((a, b) => a + b, 0);

1function addArrayNums(arr) {
2	let total = 0;
3	for (let i in arr) {
4      total += arr[i];
5    }
6  return total;
7}