获取JSON列的数组并检查重复项/ VueJS

data() {
  return {
    jsonArr: [
      { id: 1, name: 'John' },
      { id: 2, name: 'Jane' },
      { id: 3, name: 'John' }
    ]
  }
}

computed: {
  duplicateItems() {
    return this.jsonArr.filter((item, index) => {
      return this.jsonArr.findIndex(obj => obj.name === item.name) !== index;
    });
  }
}

<div>
  <ul>
    <li v-for="item in duplicateItems" :key="item.id">
      {{ item.name }} is a duplicate.
    </li>
  </ul>
</div>