Improving Code Quality - Session 52: Pruning Branches and Cleaning Roots

In a situation where multiple UI elements such as background color, icon, and text need to change depending on the account type (Free, Business, Premium), you need to think about how to structure the code.

There are largely two ways to implement this. Option 1 (cutting vertically), which splits code blocks by account type, and Option 2 (cutting horizontally), which splits code blocks by UI element.

As a result of the analysis, Option 2 is far more advantageous in terms of readability and stability.

• Readability: By reading just the main function, you can clearly see which UI elements are being updated, making it easy to grasp the overall behavior without having to check every detailed implementation.
• Compile-time stability: When a new account type or UI element is added, using a when expression lets you immediately detect missing implementations at the compile stage, preventing runtime errors.

Furthermore, Option 2 also makes it easier to apply additional refactoring, such as separating side effects to make functions referentially transparent.