how to add all values of array together js

const sum = arr => arr.reduce((a, b) => a + b, 0);console.log(
  [1, 2, 3, 4].reduce((a, b) => a + b, 0)
)
console.log(
  [].reduce((a, b) => a + b, 0)
)function addArrayNums(arr) {
	let total = 0;
	for (let i in arr) {
      total += arr[i];
    }
  return total;
}