Vue.js“超出最大调用堆栈大小”错误。将数据从父级传递到子级失败

我无法将数据从父母传递给孩子。我正在使用道具，也尝试过返回数据-不走运。我有一个面板组件（它是父组件），带有数据，而panelBody组件（子组件）

面板如下：

<template>
  <div id="panel">
    <div class="panel">
      <ul>
        <li v-for="shelf in shelfs">
          <panel-body :shelf="shelf" :selected.sync="selected"></panel-body>
        </li>
      </ul>
    </div>
  </div>
</template>

<script>
import PanelBody from '../components/PanelBody'
export default {
  name: 'panel-body',
  components: {
    'panel-body': PanelBody
  },
  data: () => ({
    shelfs: [{
      name: 'shelf 1',
      books: [{
        title: 'Lorem ipum'
      }, {
        title: 'Dolor sit amet'
      }]
    }, {
      name: 'shelf 2',
      books: [{
        title: 'Ipsum lorem'
      }, {
        title: 'Amet sit dolor'
      }]
    }],
    selected: {}
  })
}
</script>

<style scoped>
a {
  color: #42b983;
}
</style>

我的panelBody是：

<template>
  <div id="panel-body">
    <a href="#" v-on:click.prevent.stop="select">{{ shelf.name }}</a>
    <ul v-show="isSelected">
      <li v-for="book in shelf.books">{{ book.title }}</li>
    </ul>
  </div>
</template>

<script>
export default {
  name: 'panel-body',
  props: ['shelf', 'selected'],
  computed: {
    isSelected: function () {
      return this.selected === this.shelf
    }
  },
  methods: {
    select: function () {
      this.selected = this.shelf
    }
  }
}
</script>

<style scoped>
a {
  color: #42b983;
}
</style>

请帮忙！无法找出错误“ vue.esm.js？65d7：3877 Uncaught RangeError：超出最大调用堆栈大小”。当我删除数据时，一切正常进行。