how to find array and add values in javascript code example

Example 1: add all elements in array javascript

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

Example 2: sum all elements in array javascript

arr.reduce((a, b) => a + b)