<template lang="">
  <div>
    <div
    ref="triggerNode"
    >
      <slot>aaa</slot>
    </div>
    <div 
    ref="popperNode">
      <slot>popper</slot>
    </div>
  </div>
</template>
<script setup lang="ts">
import type { Instance } from '@popperjs/core'
import { createPopper } from '@popperjs/core'
import { ref, onMounted } from 'vue'
defineOptions({
  name: 'ElTooltip'
})
const triggerNode = ref<HTMLElement>()
const popperNode = ref<HTMLElement>()
let popperInstance: Instance | null = null

onMounted(() => {
  if (triggerNode.value && popperNode.value) {
    popperInstance = createPopper(triggerNode.value, popperNode.value, {
      placement: "right"
    });
  }

});

</script>

示例代码如上，此时会超过屏幕，popper显示在最右边。