<template>
  <div>
    <button>是多少：{{count}}</button>
  </div>
</template>
<script>
import {ref, computed} from 'vue'
export default () {
const count = ref(1)
const plusOne = computed(() => count.value + 1)
}
console.log(plusOne.value) // 2

plusOne.value++ // 错误

</script>

js

const count = ref(1)
const plusOne = computed(() => count.value + 1)

console.log(plusOne.value) // 2

plusOne.value++ // 错误