vue单行文本溢出会出现title提示自定义指令

<template>
  <div class="parent">
    <h3>古诗：</h3>
    <div class="child" :title="msg">
      {{ msg }}
    </div>
  </div>
</template>
<script>
export default {
  data() {
    return {
      msg: "更上一层楼",
    };
  },
};
</script>
<style>
.parent {
  display: flex;
  align-items: center;
  width: 200px;
}
.child {
  flex: 1;
}
</style>

directives: {
    ellipsis: {
        inserted: function (el, binding) {
            // 设置超出隐藏
            el.style.overflow = "hidden";
            el.style.textOverflow = "ellipsis";
            el.style.whiteSpace = "nowrap";
            // 鼠标移入提示title
            if (el.clientWidth < el.scrollWidth) {
              el.title = el.innerhtml;
            }
        },
    },
},

<div class="child" v-ellipsis>
    {{ msg }}
</div>

msg: "白日依山尽，黄河入海流。欲穷千里目，更上一层楼",