Explore five advanced Clean Code principles, focusing on eliminating bad comments, consistent formatting, proper error handling with exceptions, and separating configuration from business logic.

While meaningful naming and short functions are the foundation of Clean Code, true software craftsmanship lies in the details—how you handle comments, structure your files, and manage unexpected errors. These practices drastically reduce the "WTFs per minute" for anyone reading your code, including your future self. Here are five advanced principles to make your code genuinely maintainable:

1. 1. Eliminate Bad Comments (Don't Excuse Dirty Code)

   A common mistake is using comments to mask poor code. Avoid using comments to explain *what* the code does (the code should speak for itself) or to justify bad decisions. Use comments only for **legal notes**, **warnings about side-effects**, or to explain **why** a specific non-obvious solution was chosen (e.g., performance constraints).

2. 2. Maintain Consistent Vertical Formatting

   Vertical density matters for readability. Code related to the same concept should be vertically close together (e.g., instance variables followed by constructors, followed by public methods). Use blank lines to separate conceptually distinct sections of code, marking the start of a new, major thought.

3. 3. Handle Errors with Exceptions (Not Error Codes)

   When something goes wrong, **throw an exception** rather than returning a confusing error code (like `-1` or `null`). Using exceptions makes the error condition explicit and forces the caller to acknowledge and handle the failure, preventing silent bugs from propagating through the system.

4. 4. Separate Configuration Logic from Business Logic

   Hardcoding settings like database URLs, API keys, or environment-specific values directly into your main business logic is a major maintainability flaw. Separate all configuration variables into dedicated files (like `.env` or configuration classes). This allows changes to be made without modifying and redeploying core code.

5. 5. Write Descriptive Unit Tests First (Test-Driven Development)

   Clean code and good tests are inseparable. Use **descriptive test names** (e.g., `test_order_fails_when_product_is_out_of_stock`) that clearly document the expected behavior of the code. Writing tests first (TDD) forces you to design smaller, testable, and therefore cleaner functions.

🛠️ Clean code is a mindset shift from "making it work" to "making it right." These principles move you toward a more robust and less frustrating development environment.