vuex提交mutation失效

Question

main.js

import Vue from 'vue'
import Vuex from 'vuex'
import VueResource from 'vue-resource'
import router from './router'
import store from './store'
import App from './App'

Vue.use(VueResource)

new Vue({
  router,
  store,
  ...App
}).$mount('#app')

store.js

import Vue from 'vue'
import Vuex from 'vuex'

Vue.use(Vuex)

const store = new Vuex.Store({
  state: {
    userState: false
  },
  mutations: {
    handleUserState: userState => !userState
  }
})
export default store

组件内调用：

this.$store.commit('handleUserState')

奇怪的是，之前在store.js内容还在main.js里的时候可以正常

Answer 1

handleUserState:state=>{
     state.userState=!state.userState
}