server.js

// CONTACTS API ROUTES BELOW

//Generates error handler used by all endpoints.
function handleError(res, reason, message, code) {
  console.log("ERROR: " + reason);
  res.status(code || 500).json({"error": message});
}

app.get("/api/contacts", function(req, res) {
  db.collection(CONTACTS_COLLECTION).find({}).toArray(function(err, docs) {
    if (err) {
      handleError(res, err.message, "Failed to get contacts.");
    } else {
      res.status(200).json(docs);
    }
  });
});

app.post("/api/contacts", function(req, res) {
  var newContact = req.body;

  if (!req.body.name) {
    handleError(res, "Invalid user input.", "Must provide a name.", 400);
  }

  db.collection(CONTACTS_COLLECTION).insertOne(newContact, function(err, doc) {
    if (err) {
      handleError(res, err.message, "Failed to create a new contact.");
    } else {
      res.status(201).json(doc.ops[0]);
    }
  });
});

app.get("/api/contacts/:id", function(req, res) {
});

app.put("/api/contacts/:id", function(req, res) {
});

app.delete("/api/contacts/:id", function(req, res) {
});