How your code makes decisions — and how you can tell it exactly what to do.

Here's something that blew my mind when I first started learning JavaScript: code doesn't just run top to bottom and call it a day. It can think . Well, not actually think — but it can make decisions based on conditions. "Is the user logged in? Show the dashboard. Not logged in? Show the login page."

That decision-making ability is called control flow , and it's what separates a static script from an actual, useful program. In the ChaiCode Web Dev Cohort 2026, this was the moment JavaScript stopped feeling like a calculator and started feeling like a real programming language.

Let's break it all down.

What Is Control Flow?

In everyday life, you make decisions constantly:

"If it's raining, I'll take an umbrella. Otherwise, I'll leave it at home."

"If my marks are above 90, I'll celebrate. If they're above 60, I'll be satisfied.…