父组件

<component ref="xponent" /><script lang="ts" setup>
import { ref } from "vue";
const xponent = ref();const download = async () => {console.log(xponent)xponent.value.download()
}
</script>

子组件核心方法，多个defineExpose对外暴露方法就行

import { defineExpose } from "vue";const download = () => {alert("下载")
}defineExpose({download
})