渲染函数出错：＆＃34; TypeError：无法读取属性＆＃39; indexOf＆＃39;未定义＆＃34;

Question

我的Vue应用程序使用了firebase，我遇到了麻烦。我现在已经使快照正常工作并且正在接收我转换为数组的对象。唯一的问题是，当我尝试过滤对象时，我得到一个＆＃34;无法读取属性＆＃34; indexOf＆＃34;未定义＆＃34;该函数正常打印出阵列，并且看起来就像我需要的那样，我只能通过包含来访问它。值得一提的是，如果我输入0,1,2,3而不是i，它就不会抛出错误。

这是我的Vuex导出器，其中包含我的Firebase快照

const users = db.ref('users')

users.on('value', function (snapshot) {
  store.state.lawyers = Object.values(snapshot.val())
  console.log('called')
})
export const store = new Vuex.Store({
  state: {
    lawyers: '',
    selectedLawyerIndex: 1,
    selectedCategory: 'Contracts'
  },
  getters: {
    getLawyers: state => {
      console.log('state ' + state.lawyers)
      return state.lawyers
    },
    getCurrentLawyer: state => {
      return state.lawyers[state.selectedLawyerIndex]
    }
}

和导致错误的函数：

export default {
  data () {
    return {
      cat: this.$store.getters.getCurrentCategory,
      lawyers: this.$store.getters.getLawyers
    }
  },
  components: {
    appLawyerWidget: LawyerWidget
  },
  methods: {
    filteredLawyers () {
      var arr = []
      console.log(this.lawyers)
      for (var i = 0; i < this.lawyers.length; i++) {
        console.log(JSON.stringify(this.lawyers[i].catarray))
        if (JSON.stringify(this.lawyers[i].catarray).indexOf(this.cat) >= 0) {
          arr.push(i)
        }
      }
      return arr
    }
  }
}

任何指针都会非常感激。谢谢！