Error-Cure

Error-Cure is a robust library for handling errors in Node.js and Express applications. It simplifies error management by providing custom error classes, middleware for centralized error handling, and utilities for logging errors and managing unhandled exceptions.

Features

• Custom Error Classes: Includes AppError, ValidationError, AuthError, and more to cover diverse use cases.
• Global Error Handler Middleware: Simplifies error handling in Express.js applications.
• Error Logging Utilities: Write errors to log files for better debugging and analysis.
• Unhandled Exception Management: Tools to handle unhandled promise rejections and uncaught exceptions.
• Lightweight & Extendable: Easy to integrate and customize for your application.

Installation

To get started, install the package using npm or yarn:

npm install error-cure

or

yarn add error-cure

Usage

1. Custom Error Classes

Error-Cure includes several custom error classes that extend a base AppError class. These can classify and handle different types of errors efficiently.

Example: AppError

The AppError class is the base for all errors in the package. It accepts a message, status code, and optional details.

const { AppError } = require('error-cure');

const error = new AppError('Something went wrong', 500);
console.log(error.message); // "Something went wrong"
console.log(error.statusCode); // 500
console.log(error.status); // "error"

Example: ValidationError

The ValidationError class tracks validation-specific errors.

const { ValidationError } = require('error-cure');

const error = new ValidationError('Invalid input', 'email', { expected: 'email format' });
console.log(error.message); // "Invalid input"
console.log(error.field); // "email"
console.log(error.details); // { expected: 'email format' }

Example: AuthError

The AuthError class handles authentication-related errors.

const { AuthError } = require('error-cure');

const error = new AuthError('Authentication failed');
console.log(error.message); // "Authentication failed"
console.log(error.statusCode); // 401

Example: DatabaseError

The DatabaseError class handles database-related errors and accepts an optional query string.

const { DatabaseError } = require('error-cure');

const error = new DatabaseError('Database connection failed', 'SELECT * FROM users');
console.log(error.message); // "Database connection failed"
console.log(error.query); // "SELECT * FROM users"

2. Global Error Handler Middleware

The global error handler middleware is designed for Express.js applications. It formats errors and sends appropriate responses.

Example: Express Integration

In your app.js or server.js file:

const express = require('express');
const { globalErrorHandler } = require('error-cure');

const app = express();

// Example route that throws an error
app.get('/', (req, res, next) => {
  const error = new Error('Something went wrong!');
  error.statusCode = 500;
  next(error);
});

// Global error handling middleware
app.use(globalErrorHandler);

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

The middleware formats and returns the error response based on whether it’s operational or not.

3. Error Logging Utility

The logging utility writes errors to a log file for debugging.

Example: Logging Errors

const { logError } = require('error-cure');

try {
  throw new Error('Something bad happened');
} catch (err) {
  logError(err);
}

This will append the error to an error.log file in the project root directory.

4. Handle Unhandled Rejections & Exceptions

Error-Cure provides utilities to handle unhandled promise rejections and uncaught exceptions globally.

Example: Handling Unhandled Rejections

In your index.js or app.js file:

const { handleUnhandledRejections } = require('error-cure');

// Automatically handle unhandled promise rejections
handleUnhandledRejections();

This ensures that unhandled promise rejections are logged and processed correctly.

Testing

To ensure the package works as expected, run tests using the following command:

npm test

Running Tests with Jest

If you have Jest configured, run:

npx jest

Write tests for each error class and utility to maintain robustness.

Contributing

We welcome contributions! Follow these steps:

1. Fork the repository.
2. Clone your fork.
3. Create a new branch for your feature or bug fix.
4. Commit your changes and push the branch.
5. Submit a pull request.

Please adhere to our Code of Conduct.

License

Error-Cure is licensed under the MIT License. See the LICENSE file for details.

Keywords

Node.js, Express, error handling, middleware, error classes, global error handling, logging, unhandled exceptions, validation errors, authentication errors.

Links

• GitHub Repository

Simplify and strengthen error handling in your Node.js and Express applications with Error-Cure. Get started today!