JS Built-ins
← Closures1 / 20
Closuresbeginner

Closures — Basic counter

📖 Usage Example
function makeCounter() {
  let n = 0
  return () => ++n
}
const counter = makeCounter()
counter()  // → 1
counter()  // → 2

The counter closure keeps its own private count variable, so each call increments independently without any global state.

Creating a Simple Counter with Closures

A closure is a function that has access to variables from its outer scope even after the outer function has returned.

Challenge: Create a makeCounter function that returns a function. Each time the returned function is called, it should increment and return a counter starting from 1.

Example:

const counter = makeCounter()
counter() // 1
counter() // 2
counter() // 3
💡 Hints (2)
  • • Use a variable outside the returned function to store state
  • • Each call to makeCounter should create a new independent counter