vuex_store.js

import vuex from 'vuex'

const state = {
    userInfo: {},
}

const mutations = {
    updateUserInfo(state, userInfo) {
        state.userInfo = userInfo;
    },
}

const getters = {
    userInfo: state => {
        return state.userInfo;
    },
}

const actions = {
    updateUserInfo: ({commit}, payload) => {
        commit('updateUserInfo', payload);
    }
}

export default new vuex.Store({
    state,
    actions,
    getters,
    mutations,
})

main.js

....
import {createApp} from 'vue'
import App from './App.vue'

import vuex from 'vuex'
import mitt from 'mitt';

import vuexStore from './common/vuex_store'
import {router} from './common/router';

router.beforeEach((to, from, next) => {
    const title = to.meta && to.meta.title;
    if (title) {
        document.title = title;
    }
    next();
});

// export default mitt();
const app = createApp(App);
app.use(router);
app.use(vuex);
app.use(vuexStore); //这里注册进来
app.config.globalProperties.$bus = mitt();
app.config.globalProperties.$showLoading = "showLoading";
app.mount('#app'); 

要使用的js

<script>
import {mapGetters} from "vuex";

export default {
  created() {
    this.$store.dispatch("updateUserInfo", {"name": "DaiYao"});
    console.log("打印用户信息：> " + this.userInfo.name)
  },
  computed: {
    ...mapGetters(["userInfo"])
  }
}
</script>