Fixes bug where requestsOfType() would fail if no body

- Passes if request has no body
- Returns a JSON object with an error message when request
  doesn't match type, the response body was "[object Object]"

server/server.js

@@ -138,6 +138,17 @@ app.get('/', (req, res) => {
   res.sendFile(renderIndex());
 });
 
+// Handle API errors
+app.use('/api', (error, req, res, next) => {
+  if (error && error.code && !res.headersSent) {
+    res.status(error.code).json({ error: error.message });
+    return;
+  }
+
+  next(error);
+});
+
+
 // Handle missing routes.
 app.get('*', (req, res) => {
   res.status(404);

server/utils/requestsOfType.js

@@ -4,11 +4,14 @@
   header does not match `type`
 */
 const requestsOfType = type => (req, res, next) => {
-  if (req.get('content-type') != null && !req.is(type)) {
+  const hasContentType = req.get('content-type') !== null;
+  const isCorrectType = req.is(type) === null || req.is(type) === type;
+
+  if (hasContentType && !isCorrectType) {
     if (process.env.NODE_ENV === 'development') {
-      console.log('in requests of type error');
+      console.error(`Requests with a body must be of Content-Type "${type}". Sending HTTP 406`);
     }
-    return next({ statusCode: 406 }); // 406 UNACCEPTABLE
+    return next({ code: 406, message: `Requests with a body must be of Content-Type "${type}"` }); // 406 UNACCEPTABLE
   }
 
   return next();