text: // mutation必须是同步操作。异步操作需使用action
  
  const SOME_MUTATION = 'SOME_MUTATION'
  export default {
    increment(state, payload) {
      state.count++
    },
    changeItemInfo(state, val) {
      state.item_info = val
    },
    [SOME_MUTATION](state) {
      // mutate state
    }
  }
  