element-plus/docs/examples/dialog/nested-dialog.vue

<template>
  <el-button type="text" @click="outerVisible = true"
    >open the outer Dialog</el-button
  >

  <el-dialog v-model="outerVisible" title="Outer Dialog">
    <template #default>
      <el-dialog
        v-model="innerVisible"
        width="30%"
        title="Inner Dialog"
        append-to-body
      >
      </el-dialog>
    </template>
    <template #footer>
      <div class="dialog-footer">
        <el-button @click="outerVisible = false">Cancel</el-button>
        <el-button type="primary" @click="innerVisible = true"
          >open the inner Dialog</el-button
        >
      </div>
    </template>
  </el-dialog>
</template>

<script lang="ts">
import { defineComponent, ref } from 'vue'

export default defineComponent({
  setup() {
    return {
      outerVisible: ref(false),
      innerVisible: ref(false),
    }
  },
})
</script>