ts-express-error-handler

A comprehensive error handling package for Express applications written in TypeScript. This package provides a set of custom exceptions, a translation service for internationalization, and a centralized error handling middleware.

Features

• Custom exception classes for common HTTP error scenarios
• Built-in translation service for easy internationalization
• Centralized error handling middleware
• TypeScript support

Installation

npm install ts-express-error-handler

Usage

Basic Setup

import express from "express";
import { errorHandler, NotFoundException } from "ts-express-error-handler";

const app = express();

app.get("/test", (req, res, next) => {
  next(new NotFoundException());
});

app.use(errorHandler);

app.listen(3000, () => console.log("Server running on port 3000"));

Custom Exceptions

The package includes the following custom exceptions:

• BadRequestException (400)
• UnauthorizedException (401)
• UnauthenticatedException (401)
• ForbiddenException (403)
• NotFoundException (404)
• ValidationException (422)

You can throw these exceptions in your route handlers or middleware:

import { BadRequestException } from "ts-express-error-handler";

app.get("/example", (req, res, next) => {
  if (!req.query.id) {
    throw new BadRequestException("ID is required");
  }
  // ... rest of your code
});

Translation Service

The package includes a built-in translation service for internationalization:

import { translationService } from "ts-express-error-handler";

// Add custom translations
translationService.addTranslation("custom.error", {
  ar: "خطأ مخصص",
  en: "Custom Error",
  es: "Error personalizado",
  fr: "Erreur personnalis e",
});

// Use in your code
const errorMessage = translationService.translate("custom.error", "es");
console.log(errorMessage); // Outputs: "Error personalizado"

Error Handler Middleware

The errorHandler middleware will catch any thrown exceptions, translate the error messages based on the Accept-Language header, and send an appropriate JSON response:

app.use(errorHandler);

API Reference

Exceptions

• BadRequestException(message?: string)
• UnauthorizedException(message?: string)
• ForbiddenException(message?: string)
• NotFoundException(message?: string)
• ValidationException(message?: string, errors?: ValidationError[])

Translation Service

• translationService.addTranslation(key: string, translations: { [lang: string]: string })
• translationService.translate(key: string, language: string): string

Error Handler

• errorHandler(err: Error, req: Request, res: Response, next: NextFunction)

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

License

This project is licensed under the MIT License.

Feedback and Contributions

If you have any feedback or suggestions, feel free to open an issue or submit a pull request. Contributions are more than welcome!

Developed with ❤️ by Mohamad Almoayad.