errorHandler.js

// middleware/errorHandler.js
// Centralized Express error handler. Any error thrown (or passed to next())
// anywhere in the app ends up here, giving a consistent JSON error response.

const notFound = (req, res, next) => {
  const error = new Error(`Route not found - ${req.originalUrl}`);
  res.status(404);
  next(error);
};

const errorHandler = (err, req, res, next) => {
  // If a status code was already set (e.g. 401, 403) keep it, otherwise default to 500
  const statusCode = res.statusCode && res.statusCode !== 200 ? res.statusCode : 500;

  res.status(statusCode).json({
    success: false,
    message: err.message,
    stack: process.env.NODE_ENV === 'production' ? undefined : err.stack,
  });
};

module.exports = { notFound, errorHandler };