how to add all values in an array together 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: how to add up all numbers in an array

const numbers = [10, 20, 30, 40] 
add = (a, b) =>  a + b
const sum = numbers.reduce(add)