如何从父组件中的子元素中获取累积高度

<template>
  <div>
    <child-component ref="childRef"></child-component>
    <p>累积高度: {{ totalHeight }}px</p>
  </div>
</template>

<script>
import ChildComponent from './ChildComponent.vue';

export default {
  components: {
    ChildComponent
  },
  data() {
    return {
      totalHeight: 0
    };
  },
  mounted() {
    this.calculateTotalHeight();
  },
  methods: {
    calculateTotalHeight() {
      this.totalHeight = this.$refs.childRef.$el.offsetHeight;
    }
  }
};
</script>

<template>
  <div>
    <!-- 子组件内容 -->
  </div>
</template>

<script>
export default {
  mounted() {
    this.$parent.calculateTotalHeight();
  },
  updated() {
    this.$parent.calculateTotalHeight();
  }
};
</script>