JavaScript Closures — Explained with a Bank Account You'll Never Forget

Hey! Before we start — have you ever tried to understand closures and ended up more confused than before? Yeah. Most beginners have. And it's not your fault. The definitions are dry. The examples feel random. Nothing clicks . So today, let's skip the textbook stuff. We'll use a real bank account to understand closures — step by step, together. 1. What Is a Closure? Here's the simplest way to think about it. Imagine a bank. When you open an account, the bank keeps your balance locked inside a private vault. You can't just walk in and grab it. You have to go through the bank's system — deposit, withdraw, check balance. That vault? That's a closure in JavaScript. A closure is when an inner function remembers the variables from its outer function — even after the outer function has stopped running. We'll see exactly what that means in code. Keep reading. 2. Here's Our Bank Account Code Let's look at the full example first. Don't worry if you don't get everything right away — we'll walk thr