Here we define some of common functional-style programming code smells.

1. Too many indentation levels (deep nesting).
2. Too long functions/components.
3. Too many parameters/props.
4. Too many comments.
5. String literals instead of constants/internalization.
6. Too complex (hard to understand) code.
7. Dead code.
8. Violating naming conventions/too short names.
9. Too many useState.
10. Overusing the Render Props or the HoC patterns.
11. Mixing view and view-controller (smart and dumb components) in one component.
12. Reckless on file structure.
13. Circular dependencies.
14. Code duplication (if it's not a matter of clarity).

• Code Smells (for OOP mostly)