qapinterface/lib/http/error-middleware.js

Comprehensive API utilities for Node.js applications including authentication, security, request processing, and response handling with zero external dependencies

/**
 * Error Handling Middleware
 * Single Responsibility: Generic Express error handling middleware
 */

const { logger } = require('../asyncLogger');
const { createErrorResponse } = require('./error-response-creator');

/**
 * A generic error handling middleware for Express.
 * This should be the last middleware added to the app.
 * @param {Error} err - The error object.
 * @param {object} req - The Express request object.
 * @param {object} res - The Express response object.
 * @param {function} next - The Express next function.
 */
function errorHandlerMiddleware(err, req, res, next) {
  // Log the error with request context
  logger.error({
    err,
    req: {
      id: req.id,
      method: req.method,
      url: req.originalUrl,
      ip: req.ip,
    }
  }, 'An unexpected error occurred');

  if (res.headersSent) {
    return next(err);
  }

  res.status(500).json(createErrorResponse('Internal Server Error'));
}

module.exports = {
  errorHandlerMiddleware
};