quickstruc/boilerplate/node/typescript/middlewares/globalErrorHandler.ts

quickstruc is a Node.js-powered module designed to streamline project scaffolding.

import { Request, Response, NextFunction } from "express";
import AppError from "../utils/AppError";

/**
 * Global error handler middleware for handling errors across the application.
 *
 * @param {Error} err - The error object that contains error details, including message, stack, status code, etc.
 * @param {Request} req - The request object, which contains information about the HTTP request, such as headers, body, and query parameters.
 * @param {Response} res - The response object, which is used to send a response back to the client.
 * @param {NextFunction} next - The next middleware function, which can be called to pass control to the next middleware.
 */
const globalErrorHandler = (
  err: AppError, // Error can be AppError (custom) or a generic Error
  req: Request,
  res: Response,
  next: NextFunction
): void => {
  // Set the default status code if it's not set
  err.statusCode = (err as AppError).statusCode || 500;
  err.status = (err as AppError).status || "error";

  // Log the error (for development or production)
  if (process.env.NODE_ENV === "development") {
    console.error("ERROR 💥:", err);
  } else {
    // Log detailed errors in production
    if ((err as AppError).isOperational) {
      console.error("ERROR 💥:", err);
    } else {
      // Log the entire error stack for unknown errors
      console.error("ERROR 💥:", (err as Error).stack);
    }
  }

  // Send a response with the error details
  res.status((err as AppError).statusCode).json({
    status: (err as AppError).status,
    message: err.message,
    ...(process.env.NODE_ENV === "development" && {
      stack: (err as Error).stack,
    }), // Include stack trace in development mode
  });
};

export default globalErrorHandler;