vue3-admin/src/views/Dashboard/index.vue

<template>
  <el-button>DashBoard</el-button>
  <el-button @click="handle"></el-button>
</template>
<script lang="ts" setup>
const a = ref(1);
const { proxy } = getCurrentInstance()!;

const handle = () => {
  proxy?.$message({
    message: "Hello World!" + a.value
  });
};
</script>