sum function in javascript code example

Example 1: array sum javascript

const arr = [1, 2, 3, 4];
const sum = arr.reduce((a, b) => a + b, 0);
// sum = 10

Example 2: javascript sum of array

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

Example 3: sum javascript

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

Example 4: sum function in javascript

let sum = (...para) => para.reduce((d,b) => d + b);

Example 5: summation js

const summation = (n) => (n * (n + 1)) / 2;