sum numbers javascript code example

Example 1: js sum of array

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

// Output: 10

Example 2: javascript sum of array

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

Example 3: sum of all numbers in an array javascript

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

Example 4: summation js

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