Cannot read property 'length' of undefined in ionic vue

i am using Ionic vue to create app, in that i am using ionic tabs, suddenly i got below error

    at t.tabDidLoad (baecuvvq.js:5)
    at ionic.eng0ita3.js:9
    at HTMLElement.u (ionic.eng0ita3.js:9)
    at Object.d.emit [as Xa] (ionic.eng0ita3.js:34)
    at Object.emit (ionic.eng0ita3.js:23)
    at baecuvvq.js:5

below is my code

  <ion-tab tab="home" >Home Content</ion-tab>
  <ion-tab tab="settings">Settings Content</ion-tab>

  <ion-tab-bar slot="bottom">

    <ion-tab-button tab="home">
      <ion-icon name="home"></ion-icon>

    <ion-tab-button tab="settings">
      <ion-icon name="settings"></ion-icon>


export default {
    name: 'myride',
    components: {

    props: {

    data: function(){
        return {}
    methods: {



Please help me anyone it’s urgent