如何使用带有组合API的Vue 2键入提示vue组件方法

Question

我有两个组件

简化示例（我忽略了应用程序初始化）：

<template>
   <div ref="modalEl">I'm the modal<slot></slot></div>
</template>
<script lang="ts">
import {defineComponent, onMounted, ref} from '@vue/composition-api';
import Modal from 'bootstrap/js/dist/modal';

export default defineComponent({
    setup(props) {
       const modalEl = ref<Element | string>('');
       let modal: Modal;

       onMounted(() => {
          modal = new Modal(modalEl.value);
       });

       const show = () => modal.show();

       return {
          modalEl,
          show,
       } 
    }
});
</script>

<template>
   <div>
       <Modal ref="modalSave">I'm modal content</Modal>
       <button @click="showModal">show modal</button>
   </div>
</template>
<script lang="ts">
import {ref,defineComponent} from '@vue/composition-api';
import Modal from 'Modal.vue';
export default defineComponent({
  components: {
      Modal
  },
  setup(props) {
      const modalSave = ref<InstanceType<typeof Modal> | null>(null);
      const showModal = () => modalSave.value?.show();

      return {
          modalSave,
          showModal
      }
  }
});

</script>

如前所述，它可以工作，我甚至可以在PhpStorm中完成代码。但当我编译时，我得到了一个错误：

应用程序中出现错误。vue。ts（115,24）TS2339:属性'show'在类型{readonly$el:Element；readonly$options:{data？：DefaultData |未定义；props？：string[]|{[x:string]：Prop |{type？：Prop | Prop[]未定义；必需？：boolean |未定义；默认？：any；any；validator:（（值：any）=

有人知道如何在这里不添加ts ignore而让TypeScript快乐吗？