路由之前的Vue js

我正在为我的应用程序使用laravel和vuejs,每个用户都有一个角色。现在,我想通过将用户重定向到另一个路由(如果他们无法访问页面)来限制用户按其角色访问vue路由。我正在为vuejs使用beforeRouteEnter,但出现了一个错误

data() {
    return{
      role: '',
    }
  },
mounted() {
    axios.post('/getRole')
    .then((response) => this.role = response.data)
    .catch((error) => this.errors = error.response.data.errors)
  },

beforeRouteEnter (to, from, next) {
    if (this.role === 'Admin') {
      next()
    }else {
      next('/')
    }
}

我收到了这个错误

app.js:72652 TypeError: Cannot read property 'role' of undefined
    at beforeRouteEnter (app.js:90653)
    at routeEnterGuard (app.js:72850)
    at iterator (app.js:72690)
    at step (app.js:72464)
    at runQueue (app.js:72472)
    at app.js:72726
    at step (app.js:72461)
    at app.js:72465
    at app.js:72711
    at app.js:72539