Simple examples of Array::reduce

simpleReduce.js

const numbers = [1, 3, 5, 1, 23, 5]

// Adds two args
const add = (one, two) => one + two

// Compute sum of the collection
const sum = numbers.reduce((sum, number) => add(sum, number))

// Multiplies two args
const multiply = (one, two) => one * two

// Compute product of the collection
const product = numbers.reduce((product, number) => multiply(product, number))