store->index.js

export default new Vuex.Store({
  state,
  mutations,
  actions,
  modules: {
    user
  }
})
 

user.js

const state = {
  userName: 'ReSword'
}
const mutations = {
  //
}
const actions = {
  //
}

export default {
  namespaced: true,
  state,
  mutations,
  actions
}
 

xxxx组件

import { createNamespacedHelpers } from 'vuex'

computed: {

const { mapState } = createNamespacedHelpers('user')

        ...mapState({
            userName: state => state.userName
        })

}

或者

import { mapState } from 'vuex'

computed: {

...mapState('user', {
            userName: state => state.userName
        })

}