# Closures — JavaScript

Source: https://www.geekswithgeeks.com/en/javascript/js-closures

> Functions that remember their environment.

## What is a closure?

A closure is a function that **remembers** the variables from where it was created, even after that outer function has returned.

## A counter with closures

Each call to `makeCounter()` creates its own private `count` that only the returned function can touch.

```js
function makeCounter() {
  let count = 0;
  return function () {
    count += 1;
    return count;
  };
}
const counter = makeCounter();
console.log(counter());  // 1
console.log(counter());  // 2
```

## A private backpack

Think of a closure as a **backpack** the inner function carries — it packs the variables it needs from the outer scope and keeps them, private, wherever it goes.

**Quiz:** In the counter example, why does calling counter() a second time return 2, not 1?

- [ ] Because count resets every call
- [x] Because the closure keeps count alive between calls
- [ ] Because JS caches the last return value

*Answer:* Because the closure keeps count alive between calls. The inner function closes over `count`, so it persists across separate calls to `counter()`.