Counter Function: makeCounter

Goal: create a function makeCounter(initialValue = 0) that returns a counter function. The first call returns the initial value (or 0), each subsequent call returns a value 1 greater. Each counter is independent.

function makeCounter(initialValue = 0) {
    // Private state variable — accessible only from the returned function
    let count = initialValue;
    
    // Return the counter function: returns current value, then increments
    return function() {
      return count++; // post-increment: return old value first, then increment
    };
}
  
window.makeCounter = makeCounter;

Task description

Create a function makeCounter that takes an optional integer as the initial value and returns a counter function.

How the function should work:

1. First call of the returned function should return the initial value (if provided) or 0 (if not)
2. Each subsequent call should return a value 1 greater than the previous call
3. Each counter is independent — different calls to makeCounter create separate counters

Usage examples:

Counter without initial value:

const counter = makeCounter();
counter(); // 0
counter(); // 1
counter(); // 2

Counter with initial value:

const counter = makeCounter(5);
counter(); // 5
counter(); // 6
counter(); // 7

Independent counters:

const counter1 = makeCounter(10);
const counter2 = makeCounter(20);
 
counter1(); // 10
counter2(); // 20
counter1(); // 11
counter2(); // 21

Requirements:

• The function must be named makeCounter
• Accepts one optional parameter — initial value
• Returns a function that increments the counter by 1 on each call
• If the initial value is not provided, the counter starts from 0
• Different counters must work independently