reduce.js

"use strict"

function Main(input) {
  let lines = input.split('\n');
  let A = lines[0].split(' ');
  console.log(summation(A));
  console.log(product(A));
}

function summation(a) {
  const reducer = (accumulator, currentValue) => accumulator + parseInt(currentValue, 10);
  return a.reduce(reducer, 0);
}

function product(a) {
  const reducer = (accumulator, currentValue) => accumulator * currentValue;
  return a.reduce(reducer);
}

Main(require("fs").readFileSync("/dev/stdin", "utf8"));
// This program is used on the command line.
// Usage:
// $ node recursion.js
// 1 2 3 4
// 10
// 24