Configure-Environment-Variables-Setup-Global-Error-Handling-Middleware

[shamoo53]

i have successfully completed all the required tasks for configuring environment variables and setting up global error handling middleware:

✅ Completed Tasks:
Created .env.example with all required keys:
PORT, MONGO_URI, JWT_SECRET, JWT_REFRESH_SECRET, JWT_EXPIRES_IN
EMAIL_HOST, EMAIL_PORT, EMAIL_USER, EMAIL_PASS
STELLAR_HORIZON_URL, STELLAR_NETWORK
Also included NODE_ENV and ALLOWED_ORIGINS for completeness

Created .env for local development:
Added a properly configured .env file with realistic values for local development
The file is properly added to .gitignore

Added config/env.js to validate required variables:
Created a validation function that checks for all required environment variables
Throws a descriptive error with a list of missing variables if any are missing
Exits the process with code 1 when required variables are missing
Created src/middlewares/errorHandler.js for centralized error handling:
Handles ValidationError (Mongoose validation errors)
Handles CastError (invalid ObjectId format)
Handles MongoDB duplicate key errors (11000)
Handles JWT errors (JsonWebTokenError, TokenExpiredError)

Returns consistent error shape: { success: false, message: "...", errors: [...] }
Includes stack trace in development mode for debugging
Registered middleware in app.js:
Added the error handler middleware at the bottom of app.js as required
Ensured it's registered after all routes to catch unhandled errors

🧪 Verification:
The environment variable validation successfully runs when the server starts
When required variables are missing, the application throws a descriptive error
The error handler middleware will catch and format errors consistently
All unhandled errors will return a JSON response with the correct HTTP status code
The implementation meets all acceptance criteria:
App throws a descriptive error at startup if any required env variables are missing
All unhandled errors return a JSON response with the correct HTTP status code
The error format is consistent across the application
The middleware handles the specified error types (ValidationError, CastError, MongoDB 11000 errors

Closes #2