function createCounter() {
  let count = 0;
  return {
    increment: () => ++count,
    decrement: () => --count,
    getValue: () => count
  };
}

const counter1 = createCounter();
const counter2 = createCounter();
counter1.increment();
counter1.increment();
counter2.increment();
console.log(counter1.getValue() + counter2.getValue());