Fixing the Lowercase Monster: How One Function Was Silently Breaking Multilingual Text

I was deep in the Trend Analysis project, wrestling with something that seemed simple on the surface but was causing subtle chaos across our i18n pipeline. The issue? A function called formatClassName that was supposed to just capitalize the first letter of category names. Sounds harmless, right? It absolutely wasn’t.

The culprit was buried in our codebase—a function that didn’t just capitalize the first letter; it was aggressively lowercasing everything else. When our backend sent us a perfectly formatted title like “React Native Adoption,” this function would transform it into “React native adoption.” Native, as a proper noun, lost its dignity. On the Russian side, it was even worse: carefully preserved Cyrillic capitalization from our _enforce_sentence_case() backend logic was being brutally flattened to lowercase.

I’d been staring at this for two days before the real problem clicked. We have Claude on the backend already doing sentence-case enforcement for Russian and English descriptions. The frontend didn’t need to fix what wasn’t broken—it just needed to respect what the backend already got right. So instead of trying to be clever, I simplified the entire approach: capitalize the first letter, leave everything else untouched.

The new logic was almost embarrassingly straightforward. First word gets a capital letter—that’s it. Abbreviations like “AI,” “LLM,” and “API” stay uppercase because they never got lowercased in the first place. Proper nouns like “React” and “Native” survive unmolested. Russian text keeps its character. English text flows naturally.

Testing the fix felt like watching a weight lift. “финансирование инвестиций в ИИ” now becomes “Финансирование инвестиций в ИИ” instead of “Финансирование инвестиций в ии.” “Small language models contamination” stays readable instead of becoming “Small language models contamination” with lost emphasis. The fix was so simple—three lines of actual logic—that I almost missed how much damage the old approach was doing.

The real lesson? Sometimes the best engineering isn’t about adding smarter code; it’s about removing code that shouldn’t exist. I pushed the commit, and suddenly our category display across multiple languages looked actually correct for the first time.

Programming is 10% science, 20% ingenuity, and 70% getting the ingenuity to work with the science. 😄