📌 This post is one chapter in my Red Flags series. I’m exploring the mistakes, bad practices, and subtle issues we often overlook in day-to-day development. Stay tuned for upcoming posts!
When one function tries to run the universe
If you have worked in any codebase long enough, you have probably met a "god function". It is that one function that seems to know everything, do everything, control everything and occasionally summon thunder if you are not careful.
A god function usually starts with good intentions. Someone just wants to ship a feature quickly. Then a bit of validation gets added. Then a database call. Then some business logic. Then a couple of notifications. Before you know it, the function has grown into a mythical creature that nobody wants to touch during a code review.
Here is where the real pain begins. A god function mixes responsibilities that should never live together. Reading it feels like scrolling through the entire application in one file. Testing it becomes a nightmare because you need to mock or spin up half the system just to validate a tiny behavior. A simple unit test suddenly requires databases, external services, side effects and heroic patience. And once tests become difficult, people stop writing them which leads directly to more bugs and more fear around changes.
Changing one line becomes risky because everything is tightly coupled. New developers stare at it the way tourists stare at ancient monuments: with curiosity, fear and confusion.
The good news is that god functions are not eternal. The solution is straightforward, even if it takes a bit of discipline. Break them into smaller focused functions. Group related behaviors together. Move business logic away from infrastructure and side effects. Create clear boundaries and let each function do one job well.
Once the responsibilities are separated, the code becomes readable, testable and much easier to reason about. Small functions reduce cognitive load, make refactoring safer and give your team confidence to make changes without fear.
If your function requires scroll bars and multiple coffee breaks to understand it, it might be time to break the divine cycle. Your future self and your teammates will thank you.
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