What is Code Smell and how to Fix
Code smell is a term used in software development to describe certain characteristics in the source code that may indicate the presence of a deeper problem. These characteristics don't necessarily indicate a bug, but they suggest that there might be issues with the code's design or structure. Code smells are subjective and can vary from one context to another, but they often hint at the need for refactoring or improvement in the codebase.

Here are some common code smells and strategies to fix them:

1. Duplicated Code:
- Code Smell: Repeating the same or similar code in multiple places.
- Fix: Extract the duplicated code into functions or methods. Create reusable components to reduce redundancy.

2. Long Methods or Functions:
- Code Smell: Functions or methods that are excessively long and perform too many tasks.
- Fix: Break down long functions into smaller, more focused ones. Each function should ideally perform a single responsibility.

3. Large Classes:
- Code Smell: Classes that have grown too large and handle multiple responsibilities.
- Fix: Apply the Single Responsibility Principle (SRP). Refactor the class to have a clear and specific purpose. Create new classes for additional responsibilities.

4. Nested Code or Excessive Indentation:
- Code Smell: Deeply nested if statements or loops leading to poor readability.
- Fix: Refactor nested code by breaking it into smaller functions or methods. Use guard clauses to handle special cases early.

5. Code Comments:
- Code Smell: Excessive or unclear comments that might indicate that the code itself is not self-explanatory.
- Fix: Improve code readability and clarity. Remove unnecessary comments and focus on writing expressive and self-documenting code.

6. Large Parameters List:
- Code Smell: Functions or methods with a large number of parameters.
- Fix: Combine related parameters into objects. Use structures like options objects to group related parameters.

7. Inconsistent Naming:
- Code Smell: Inconsistent naming conventions for variables, functions, or classes.
- Fix: Adopt a consistent naming convention. Choose names that accurately describe the purpose or content of the code entity.

8. Unused Code:
- Code Smell: Code that is never executed or variables that are declared but not used.
- Fix: Remove unused code. Unused functions, variables, or imports contribute to code bloat and confusion.

9. Tight Coupling:
- Code Smell: Classes or modules that are closely interdependent, making it hard to modify one without affecting the other.
- Fix: Apply the principles of loose coupling and high cohesion. Use dependency injection and interfaces to decouple components.

10. Lack of Unit Tests:
- Code Smell: Code that lacks accompanying unit tests.
- Fix: Write unit tests to ensure code correctness and facilitate future changes. Use test-driven development (TDD) to guide the development process.

Addressing code smells requires a combination of good coding practices, adherence to design principles, and regular code reviews. The goal is to create maintainable, readable, and efficient code that can adapt to changing requirements.