The Quest Begins (The "Why")
I still remember the first time I opened a pull request that looked like a novel written by someone who’d had too much coffee. The file was 800 lines long, a single function tried to validate input, fetch data from three different APIs, transform the result, update the UI, and log everything to a console that no one ever looked at. I spent three hours stepping through it with a debugger, only to realize the bug was a typo in a variable name buried three levels deep in a nested if‑statement. When I finally fixed it, I felt like I’d just defeated a dragon… only to discover the dragon had a dozen smaller dragons hiding in its caves.
That experience left me wondering: Why does code feel so hard to read, even when it works? The answer wasn’t a fancy framework or a new language feature—it was a simple habit I’d overlooked: making every function do one thing, and do it well. Once I started treating that rule like a sacred oath, the dragons started to shrink, and my code began to feel like a clean, well‑lit hallway instead of a dark, tangled forest.
The Revelation (The Insight)
The principle is straightforward, yet its impact is massive: each function should have a single responsibility. If you can describe what a function does with a single verb phrase—validateUserInput, fetchUserProfile, renderDashboard—you’re on the right track. If you need an “and” or a “but” in that description, you’ve probably got more than one job packed in.
