express-error-catcher

express-error-catcher

express-error-catcher is a robust npm package engineered to streamline error handling in Node.js Express applications. It provides an elegant solution for managing async/await errors, reducing boilerplate code, and enhancing the maintainability of your applications.

Key Features

• Automated Error Handling: Effortlessly catch and handle errors in asynchronous route handlers, allowing for cleaner and more concise code.
• Customizable Middleware: Easily configure default error messages, status codes, and logging preferences to suit your development and production environments.
• Multiple Logging Formats: Choose between detailed development logs and minimal production logs to meet your specific needs.
• Improved Code Readability: Eliminate redundant try-catch blocks, making your codebase more readable and easier to maintain.

Installation

Integrating express-error-catcher into your project is straightforward. Use the following npm command to install the package:

npm install express-error-catcher

Usage Overview

To leverage express-error-catcher in your Express application, follow these steps:

Step 1: Import the Package

Begin by importing the necessary functions and middleware from the express-error-catcher package.

import express from "express";
import { asyncErrorHandler, error, Response, Error } from "express-error-catcher";

Step 2: Configure Error Handling Middleware

Apply the error-handling middleware with optional configuration parameters to customize its behavior.

const app = express();

app.use(error({
  defaultErrorMessage: "Internal server error", // Sets a default error message for uncaught errors.
  defaultStatusCode: 500, // Defines the default HTTP status code for errors.
  log: "dev" // Chooses the logging format: "dev" for detailed logs, "prod" for concise logs.
}));

Step 3: Define Route Handlers

Use the asyncErrorHandler function to wrap your asynchronous route handlers. This ensures that any errors are automatically caught and passed to the error-handling middleware.

app.get(
  "/name",
  asyncErrorHandler((req, res) => {
    // Intentionally throwing an error
    throw Error("Error while retrieving name", 500);

    // Returning a successful response
    return Response("Successfully retrieved name", { name: "Daisy" }, 200);
  })
);

Step 4: Start the Express Server

Finally, start your Express server as usual:

const PORT = process.env.PORT || 3000;
app.listen(PORT, () => {
  console.log(`Server is running on port ${PORT}`);
});

Detailed Configuration Options

The error middleware provides a range of configuration options to tailor error handling to your application’s requirements.

• defaultErrorMessage: A string specifying the default message to return when an error is unhandled.
• defaultStatusCode: An integer representing the default HTTP status code to use when responding to unhandled errors.
• log: A string determining the log format. Options include:
  • "dev": Detailed log output for development, including error messages and file paths.
  • "pretty": A more readable format compared to dev, with enhanced formatting for better human readability. Example.
  • "production": Simplified log output for production environments, focusing on error messages only.

Logging Formats

Development (dev)

In development mode, express-error-catcher provides detailed logs that include the error message, file path, and line number, presented in a table format for easy reading:

<------------------------------->
ERROR => Internal Server Error
FILE => /path/to/file.js:16:11
<------------------------------->

Pretty (pretty)

In development mode, express-error-catcher offers detailed logs in a table format that includes the error message and file path. This format enhances readability and helps quickly identify issues:

┌─────────┬─────────────────────────┬────────────────────────────────┐
│ (index) │ Message                 │ File                           │
├─────────┼─────────────────────────┼────────────────────────────────┤
│ 0       │ 'Internal Server Error' │ '/path/to/file.js:16:11'       │
└─────────┴─────────────────────────┴────────────────────────────────┘

Production (production)

In production mode, logs are minimized to reduce noise and focus on essential information:

<------------------------------->
ERROR => Internal Server Error
<------------------------------->

Advanced Use Cases

Handling Custom Errors

express-error-catcher allows you to define and handle custom errors with specific messages and status codes, providing fine-grained control over error management.

throw Error("Custom error message", 400);

Response Format

Success Response

When an operation completes successfully, the response is structured as follows:

return new Response("Success.", { data: "Welcome daisy.." }, 200);

The corresponding JSON output will be:

{
  "code": 200,
  "success": true,
  "status": "OK",
  "message": "Success.",
  "data": "Welcome daisy.."
}

Error Response

If an error occurs during processing, an error is thrown with the following structure:

throw new Error("Daisy already exists.", 400);

The corresponding JSON output will be:

{
  "success": false,
  "code": 400,
  "status": "Bad Request",
  "message": "Daisy already exists."
}

Error Response with Additional Data

You can also include additional data in the error response for more context:

throw new Error("Daisy already exists.", 400, { details: "Validation failed" });

{
  "success": false,
  "code": 400,
  "status": "Bad Request",
  "message": "Daisy already exists.",
  "data": {
    "details": "Validation failed"
  }
}

Integrating with Other Middleware

The package is designed to integrate seamlessly with other Express middleware, allowing you to create a cohesive error-handling strategy across your application.