Vue parent and child components pass value props

Parent component Home.vue

<div id="home">
    <menutree :data="menuData"></menutree>
</div>
<script>
export default {
  components: {
    menutree: menutree
  },
  data() {
    return {
      menuData: [],
      breadcrumbText: ""
    };
  },
  methods: {
    
  },
  mounted() {
    this.menuData= JSON.parse(localStorage.getItem("menus"));
  },
  watch: {
    //监控路由，来获取面包屑导航的值
    $route(to, from) {
      for (var ele of this.menuData) {
        if (ele.children) {
          for (var ele2 of ele.children) {
            var temp = ele2.to;
            if (temp === this.$route.path)
              //如果有，就添加到路由列表里面去
              this.breadcrumbText = ele2.name;
          }
        }
      }
    }
  }
};
</script>

 Subcomponent menutree.vue

<template>
  <div>
    <el-submenu v-for="(menu,index) in data" :key="index" :index="menu.index">
        <template slot="title">
          <i class="el-icon-location"></i>
          <span>{
   
   {menu.name}}</span>
        </template>

        <el-menu-item
          v-for="(emenu,eindex) in menu.children"
          :key="eindex"
          :index="emenu.to"
        >{
   
   {emenu.name}}</el-menu-item>
    </el-submenu> 

  </div>
</template>

<script>
export default {
  name: "menutree",
  data() {
    return {
      menuData: {}
    };
  },
  props: ["data"]
};
</script>