🛡️ Error Guard

Error Guard is a lightweight, TypeScript-friendly library for standardized error handling in Node.js/Express applications.

🔄 Latest Update (v2.0.1)

ErrorGuard is now 10% faster! See full details in the CHANGELOG.md.

Installation

npm install error-guard

Environment Variables

• Make sure you have a variable named NODE_ENV in your .env file.
• When process.env.NODE_ENV !== 'production', all error objects include a full stack trace to help with debugging.
• In production, the stack field is automatically removed to prevent sensitive information from being exposed in API responses.

It provides:

• Custom error classes with HTTP status codes and error codes
• Predefined error helpers (BadRequest, ValidationError, etc.)
• Async route handler wrapper
• Express error-handling middleware

Usage

• Basic Example

import express from "express";
import {
  BadRequest,
  asyncHandler,
  createErrorHandler,
} from "error-guard";

const app = express();
app.use(express.json());

app.get(
  "/test",
  asyncHandler(async (req, res) => {
    // Throw a standardized error
    throw BadRequest("Invalid request data");
  })
);
// Global error handler
app.use(createErrorHandler());

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

• Output (JSON):

{
  "status": "fail",
  "code": "BAD_REQUEST",
  "message": "Invalid request data",
  "stack": "Error: ...",
}

Using Predefined Errors

• BadRequest(message, details) : Invalid request data
• ValidationError(message, details) : Schema or input validation failed
• AuthenticationError(message, details) : Invalid or missing credentials
• AuthorizationError(message, details) : Not allowed to perform this action
• ResourceNotFound(message, details) : Resource does not exist
• ConflictError(message, details) : Conflict with an existing resource
• RateLimitError(message, details) : Too many requests
• DependencyError(message, details) : External dependency failed
• InternalError(message, details) : Generic server error

BadRequest(message?: string, details?: any)
ValidationError(message?: string, details?: any)
AuthenticationError(message?: string, details?: any).

You can also provide optional details for more information:

throw ValidationError("Invalid email format", { field: "email" });

Async Handlers

• Wrap async route handlers to automatically catch errors:

app.get(
  "/async-test",
  asyncHandler(async (req, res) => {
    const data = await fetchData();
    if (!data) throw ResourceNotFound("Data not found");
    res.json(data);
  })
);

Custom Error Handling Middleware

• You can provide a logger to capture all errors:

app.use(createErrorHandler({
  logger: (err, req) => {
    console.error(`[${req.method}] ${req.url} -`, err);
  }
}));

API Reference

new ErrorGuard(statusCode?: number, code?: string, message?: string, details?: any)

• statusCode — HTTP status code (default: 500)
• code — Error code string (default: "ERROR")
• message — Error message
• details — Optional extra information

License

MIT License © l1l-01