package.json

{
  "name": "data-vis-intro",
  "version": "1.0.0",
  "description": "",
  "main": "server.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1",
    "start": "6to5-node server.js"
  },
  "author": "",
  "license": "MIT",
  "dependencies": {
    "express": "^4.11.2"
  }
}

random.js

var dice = function(){
	return [Math.ceil(Math.random()*6),
		Math.ceil(Math.random()*6)];
};

var add = function(x,y){ return x+y; };

exports.diceSum = function(numberOfRolls){
    if (!numberOfRolls || numberOfRolls <= 0){ return false; }
    var rollList = [];
    while (numberOfRolls-- > 0){
        rollList.push(add.apply( null, dice() ));
    }
    return rollList;
};

exports.diceSumMap = function(numberOfRolls){
    if (!numberOfRolls || numberOfRolls <= 0){ return false; }
    var rollList = [];
    while (numberOfRolls-- > 0){
        rollList.push( dice() );
    }
    return rollList.map(function(roll){
         return roll[0] + roll[1];
    }).reduce(add);
};

exports.diceSumMetaReduce = function(numberOfRolls){
    if (!numberOfRolls || numberOfRolls <= 0){ return false; }
    var rollList = [];
    while (numberOfRolls-- > 0){
        rollList.push( dice() );
    }
    return rollList.map(function(roll){
         return roll.reduce(add);
    });
// .reduce(add);
};

server.js

/* jshint esnext: true */

const express = require('express');
const random = require('./random');

var server = express();
var port = process.env.PORT || 3726;

server.get('/', function(req, res){
    res.json(random.diceSum(6));
});

server.listen(port, function(){
    console.log(`serv-ed on ${ port }`);
});