/**

• DevBuddy hint provider
• Provides hints for common error patterns */

DevBuddy 🤖

A developer-friendly runtime toolkit that intercepts JavaScript runtime errors and augments them with plain-English suggestions to help junior developers better understand and fix their code.

Features

• 🚨 Intercepts JavaScript runtime errors in Node.js
• 💡 Provides clear, actionable, beginner-friendly error explanations
• 🎯 Supports a wide range of JavaScript and Node.js error types
• 🔍 Zero-config setup - just add one line to your app
• 💻 Outputs beautiful, readable error messages with context
• 🧩 Designed for Node.js development environments

Installation

npm install devbuddy

Usage

Simply require DevBuddy at the top of your application entry point and call init():

// Add this to the top of your main file (e.g., index.js, app.js)
require('devbuddy').init();

// The rest of your application code...

That's it! DevBuddy will now intercept errors and provide helpful suggestions.

Alternative Setup in package.json

You can also apply DevBuddy throughout your application by using the --require flag in your package.json scripts:

{
  "scripts": {
    "start": "node --require devbuddy index.js"
  }
}

With this configuration, you don't need to manually add require('devbuddy').init() to your files. DevBuddy will automatically be applied when you run npm start.

Recent Updates

Enhanced System Error Detection

• Improved detection of Node.js system errors (ENOENT, ECONNREFUSED, etc.) through error code mapping
• Better identification of file system and networking error types

Improved Error Formatting

• Enhanced "HOW TO FIX IT" section with more targeted recommendations
• Reduced duplicate content in error messages
• Better readability for complex error hints

Example

Without DevBuddy, you might see an error like this:

ReferenceError: userNmae is not defined
    at Object.<anonymous> (/app.js:4:13)

With DevBuddy, you'll see:

🚨 ERROR: ReferenceError 
➤ userNmae is not defined

💡 WHY THIS HAPPENS 
  The variable "userNmae" doesn't exist in the current scope.

  Common causes:
  - The variable was never declared with let, const, or var
  - The variable name is misspelled (check for typos)
  - The variable exists in a different scope (e.g., inside a function)
  - You forgot to import a module or component
  - The variable is defined later in the code (after you try to use it)

🔧 HOW TO FIX IT 
  - Declare the variable before using it: let userNmae = value;
  - Check for spelling errors (JavaScript is case-sensitive)
  - If it's from another file, add: const userNmae = require('...')
  - Move variable declarations to the top of their scope
  - Check if you meant to use a global object like window.userNmae

📍 WHERE TO LOOK 
  → Object.<anonymous> (/app.js:4:13)

Supported Error Types

DevBuddy now supports a comprehensive range of JavaScript errors:

Core JavaScript Errors

• ReferenceError: When you use a variable that doesn't exist
• TypeError: When an operation is performed on an incompatible type
• SyntaxError: When there's a syntax mistake in your code
• RangeError: When a value is outside the allowed range
• URIError: When there's an issue with URI encoding/decoding
• EvalError: When there's a problem with the eval() function
• AggregateError: When multiple errors are wrapped into one

Node.js Specific Errors

• UnhandledPromiseRejection: When promises fail without proper error handling
• AssertionError: From Node's assert module
• ModuleNotFoundError: When modules can't be found or imported
• FileSystemError: Issues with file system operations (ENOENT, EACCES, etc.)
• NodeNetworkingError: Network-related problems (ECONNREFUSED, EADDRINUSE, etc.)

Troubleshooting Examples

Here are some common error scenarios and how DevBuddy helps:

Accessing Property on Undefined

const user = null;
console.log(user.name);

DevBuddy will tell you:

You're trying to access the property 'name' on null.

In JavaScript, you can't read properties from null. This happens when:
- An object you expected to exist is null
- An API call returned null instead of an object
- You're trying to access a deeply nested property without checking parent objects
- A function that normally returns an object returned null

How to fix:
1. Add a check before accessing the property:
   if (obj !== null) { obj.name }

2. Use optional chaining (ES2020):
   obj?.name

3. Provide a default value with nullish coalescing:
   (obj ?? {}).name

Unhandled Promise Rejection

async function getUser() {
  const response = await fetch('https://api.example.com/users/1');
  return response.json();
}
getUser(); // No error handling!

DevBuddy will tell you:

You have an unhandled Promise rejection in your async code.
This means a Promise in your code was rejected (failed), but you didn't provide error handling.

How to fix:
1. Always add .catch() handlers to your Promises:
   getUser()
     .then(user => {...})
     .catch(err => {
       console.error('Error:', err);
       // Handle the error appropriately
     });

2. When using async/await, use try/catch:
   async function doSomething() {
     try {
       const user = await getUser();
       // Process user
     } catch (err) {
       // Handle error
     }
   }

Important Notes

• DevBuddy automatically disables itself in production environments (when NODE_ENV=production)
• Only works in Node.js environments (no browser support yet)
• Does not include telemetry or remote tracking
• Does not affect your application's behavior, only enhances error output

Examples

Check out the examples directory for sample code demonstrating different error scenarios:

# Run the example to see DevBuddy in action
node examples/brokenApp.js

# Uncomment different errors in brokenApp.js to test various scenarios

Development

# Run tests
npm test

# Run linter
npm run lint

License

MIT

Roadmap

• Browser support
• Integration with popular frameworks (React, Express, etc.)
• Sourcemap integration for better error location
• Interactive mode with guided solutions
• VS Code extension integration # devbuddy

devbuddy

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