server.js

// server.js
// where your node app starts

// init project
var express = require('express');
// setup a new database
var Datastore = require('nedb'),
  // Security note: the database is saved to the file `datafile` on the local filesystem. It's deliberately placed in the `.data` directory
  // which doesn't get copied if someone remixes the project.
  db = new Datastore({ filename: '.data/datafile', autoload: true });
var app = express();

// default user list
var users = [
  {"firstName":"John", "lastName":"Hancock"},
  {"firstName":"Liz",  "lastName":"Smith"},
  {"firstName":"Ahmed","lastName":"Khan"}
];

db.count({}, function (err, count) {
  console.log("There are " + count + " users in the database");
  if(err) console.log("There's a problem with the database: ", err);
  else if(count<=0){ // empty database so needs populating
    // default users inserted in the database
    db.insert(users, function (err, usersAdded) {
      if(err) console.log("There's a problem with the database: ", err);
      else if(usersAdded) console.log("Default users inserted in the database");
    });
  }
});

// http://expressjs.com/en/starter/static-files.html
app.use(express.static('public'));

// http://expressjs.com/en/starter/basic-routing.html
app.get("/", function (request, response) {
  response.sendFile(__dirname + '/views/index.html');
});

app.get("/users", function (request, response) {
  var dbUsers=[];
  db.find({}, function (err, users) { // Find all users in the collection
    users.forEach(function(user) {
      dbUsers.push([user.firstName,user.lastName]); // adds their info to the dbUsers value
    });
    response.send(dbUsers); // sends dbUsers back to the page
  });
});

// creates a new entry in the users collection with the submitted values
app.post("/users", function (request, response) {
  db.insert({ firstName: request.query.fName, lastName: request.query.lName}, function (err, userAdded) {
    if(err) console.log("There's a problem with the database: ", err);
    else if(userAdded) console.log("New user inserted in the database");
  });
  response.sendStatus(200);
});

// removes entries from users and populates it with default users
app.get("/reset", function (request, response) {
  // removes all entries from the collection
  db.remove({}, { multi: true }, function (err) {
    if(err) console.log("There's a problem with the database: ", err);
    else console.log("Database cleared");
  });
  // default users inserted in the database
  db.insert(users, function (err, usersAdded) {
    if(err) console.log("There's a problem with the database: ", err);
    else if(usersAdded) console.log("Default users inserted in the database");
  });
  response.redirect("/");
});

// removes all entries from the collection
app.get("/clear", function (request, response) {
  db.remove({}, { multi: true }, function (err) {
    if(err) console.log("There's a problem with the database: ", err);
    else console.log("Database cleared");
  });
  response.redirect("/");
});

// listen for requests :)
var listener = app.listen(process.env.PORT, function () {
  console.log('Your app is listening on port ' + listener.address().port);
});