fix: improve error handler

backend/server.js

@@ -2,10 +2,10 @@ const express = require("express");
 const logger = require("morgan");
 const cors = require("cors");
 const mongoose = require("mongoose");
-const jsonErrorHandler = require("./services/jsonErrorHandler");
 const indexRouter = require("./routes/index");
 const usersRouter = require("./routes/users");
 const routeNotFoundJsonHandler = require("./services/routeNotFoundJsonHandler");
+const jsonErrorHandler = require("./services/jsonErrorHandler");
 
 mongoose.connect(process.env.MONGO_DB_URL, {
   useNewUrlParser: true,

backend/services/jsonErrorHandler.js

 // Custom error handler to send unhandled errors in JSON instead of HTML.
 // The error-handling middleware is a special type of Express middleware
 // that needs to have four arguments as opposed to a regular middleware.
-// eslint-disable-next-line no-unused-vars
 const jsonErrorHandler = function (error, req, res, next) {
-  console.error(error);
-  if (res.headersSent) return next(error);
-
+  if (!res.headersSent) {
     if (process.env.NODE_ENV === "development") {
-    return res.status(500).json({
-      message: error.toString(),
-      stackTrace: error.stack,
-    });
+      res.status(500).json({ message: error.toString() });
     } else {
       // Hide error details in production to avoid security issues
-    return res.status(500).json({
-      message: "Internal server error",
-    });
+      res.status(500).json({ message: "Internal server error" });
+    }
   }
+  next(error);
 };
 
 module.exports = jsonErrorHandler;