<template>
  <div>
    data == {{ data }}
  </div>
</template>

<script>
import { ref, onMounted } from 'vue';
  
export default {
  setup() {
    const data = ref(1);
    onMounted(
      () => { data.value = 2; },
    );
    return {
      data,
    }
  },
};
</script>