function createCounter() {
  let count = 0;

  return function () {
    count += 1;
    return count;
  };
}

const counterA = createCounter();
const counterB = createCounter();

console.log("counterA 第一次：", counterA());
console.log("counterA 第二次：", counterA());
console.log("counterB 第一次：", counterB());
console.log("每次调用 createCounter 都会创建一个新的闭包环境。");