Closures

A closure is a function plus the variables it remembers from where it was written. When a function returns another function (or a group of them), those inner functions keep access to the outer function's variables forever - even after the outer function has finished running and nothing else can see inside it.

That's how you get real private state in JavaScript: a variable declared inside a factory function is invisible from the outside, but any function returned from that factory can still read and change it. Call the factory again and you get a brand-new variable, completely separate from the first one - each call builds its own private world.

Your task: write makeCounter(), a function that returns an object with two methods: increment(), which adds 1 to a hidden counter and returns the new value, and value(), which returns the current count without changing it. Nothing outside the returned object should be able to read or set the counter directly.

You'll practice:

Returning functions that share one captured variable
Building private state with a closure instead of a public property

// Write makeCounter(): returns { increment(), value() } sharing one
// private counter that nothing outside the object can touch.
function makeCounter() {

}