Vue3 Script Setup 代码示例：使用 ref 和 function

<div id='app'></div>
<script>
  const { ref } = Vue;

  const App = {
    setup() {
      const count = ref(0);

      function increment() {
        count.value++;
      }

      function decrement() {
        count.value--;
      }

      return {
        count,
        increment,
        decrement
      };
    }
  };

  Vue.createApp(App).mount('#app');
</script>