把defineExpose暴露的语法注释掉之后还是报错：Cannot read properties of undefined (reading '__vccOpts')

原因：语法使用错误

Vue3.0 中变量必须 return 出来，template中才能使用。

错误代码如下：

<script lang="ts">
  const showModal = (data: any, val: string) => {
  console.log("data=====",data);
  visible.value = true;
  if (data) {
    console.log("编辑=====")
    uuid.value = data.bizCode;
    getData()
    title.value = "编辑";
    formState.value = data;
  } else {
    console.log("新增=====",val)
    title.value = "新增";
    uuid.value = val
    dataSource.value= []
    formState.value = {
      title: "",
      illustrate: "",
    };
  }
};
defineExpose({ showModal });
</script>

改正：而Vue3.2语法使用语法糖需要在 script 标签上加上 setup 属性，无需 return，template 才可直接使用。

​
<script lang="ts" setup>
  const showModal = (data: any, val: string) => {
  console.log("data=====",data);
  visible.value = true;
  if (data) {
    console.log("编辑=====")
    uuid.value = data.bizCode;
    getData()
    title.value = "编辑";
    formState.value = data;
  } else {
    console.log("新增=====",val)
    title.value = "新增";
    uuid.value = val
    dataSource.value= []
    formState.value = {
      title: "",
      illustrate: "",
    };
  }
};
defineExpose({ showModal });
</script>

​