mitt：事件总线，是第三方插件。

Vue2.x 使用 EventBus 事件总线进行兄弟组件通信，而在Vue3中 EventBus 事件总线模式已经被移除，官方建议使用外部的、实现了事件触发器接口的库，例如 mitt 或 tiny-emitter。

比起 Vue 实例上的 EventBus，mitt.js 好在哪里呢？

1. 首先它足够小，仅有200bytes。
2. 其次支持全部事件的监听和批量移除。
3. 它还不依赖 Vue 实例，可以跨框架使用，React 或者 Vue，甚至 jQuery 项目都能使用同一套库。

1、安装 mitt

npm install --save mitt

2、在公共文件 utils 下新建 mitter.ts文件，简单封装下 mitt

utils/mitter.ts

import mitt from 'mitt';const mitter = mitt();export default mitter;

3、使用

utils/request.ts

如果登录过期，派发 token-expired 事件。

import axios, { AxiosRequestConfig, AxiosResponse, AxiosError } from 'axios';
import { showMessage } from './errorCode';
import { alertController } from '@ionic/vue';
import { showToast } from '.';
import { StorageService } from './storageService';
import mitter from './mitter';let token: string = '';
// 是否显示重新登录
let isReloginShow: boolean = false;const storageService = new StorageService();
storageService.create();axios.defaults.headers['Content-Type'] = 'application/json;charset=utf-8';
// 创建axios实例
const service = axios.create({baseURL: import.meta.env.VITE_APP_ENV == 'development' ? import.meta.env.VITE_APP_BASE_API : import.meta.env.VITE_APP_BASE_URL, // 设置API的基础URLtimeout: 10000,   // 设置请求超时时间
});const presentAlert = async () => {const alert = await alertController.create({header: '系统提示',message: '登录状态已过期，您可以继续留在该页面，或者重新登录',buttons: [{text: '取消',role: 'cancel',handler: () => {console.log('Alert canceled');isReloginShow = false;},},{text: '重新登录',role: 'confirm',handler: () => {console.log('Alert confirmed');isReloginShow = false;mitter.emit('token-expired');},},],});await alert.present();
};// 请求拦截器
service.interceptors.request.use(async (config: AxiosRequestConfig): Promise<any> => {// showLoading();// 是否需要设置 token    const isToken = (config.headers || {}).isToken === falseconst headers = config.headers || {};token = await storageService.getItem("token");if (token && !isToken) {headers['Authorization'] = 'Bearer ' + token; // 让每个请求携带自定义token 请根据实际情况自行修改// headers['token'] = token;config.headers = headers;}// return new Promise((resolve, reject) => {//   resolve(config)// })return config;},(error: AxiosError) => {// 处理请求错误return Promise.reject(error);}
);// 响应拦截器
service.interceptors.response.use((response: AxiosResponse) => {// 对响应数据进行处理// 未设置状态码则默认成功状态const code = response.data.code || 200;// 获取错误信息const msg = response.data.msg || showMessage(code) || showMessage('default');// 二进制数据则直接返回if (response.request.responseType === 'blob' || response.request.responseType === 'arraybuffer') {return response.data}if (code === 401) {if (!isReloginShow) {isReloginShow = true;presentAlert();}return Promise.reject('无效的会话，或者会话已过期，请重新登录。')} else if (code === 500) {showToast(msg);return Promise.reject(new Error(msg))} else if (code !== 200) {showToast(msg);return Promise.reject('error')} else {return response.data}// return response;},(error: AxiosError) => {// 处理响应错误return Promise.reject(error);}
);export {service as request
}

src/HomePage.vue

在首页监听 token-expired 登录过期事件， 在离开页面时移出监听事件。

<script setup lang="ts">
import {IonPage,IonSearchbar,IonList,IonItem,IonLabel,IonSegment,IonSegmentButton,IonIcon,onIonViewWillEnter,onIonViewDidEnter,onIonViewWillLeave,modalController,IonNote,IonContent,IonHeader,
} from "@ionic/vue";
import { ref, inject } from "vue";
import * as echarts from "echarts";
import { StorageService } from "@/utils/storageService";
import { getAreaSituation, getCountrySamplePie, getNotify, getSampleInfo, getSampleInfoList } from "@/api/home";
import mitter from "@/utils/mitter";
import { useRouter } from "vue-router";
import HomeSearchDetails from "@/components/HomeSearchDetails.vue";
import { chevronForwardOutline } from "ionicons/icons";
import { QRScanner, registerKeyCodeReceiver, unregisterReceiver, UHFNotifyListeners, UHFRemoveAllListeners, addListenerRate, getEPC } from "@/utils/ratePlugin";
import { showToast } from "@/utils";const router = useRouter();
const keyWords = ref<string | undefined>("");
const areaList = ref<any[]>([]);
const selectedArea = ref<any>(null);
const inventoryStatisticsPieChart = ref<HTMLElement | null>(null);
let pieChart: echarts.ECharts;
const seriesData = ref<any[]>([]);
const messageList = ref<string[]>([]);
const searchList = ref<any[]>([]);
const storageService = inject("storageService") as StorageService;onIonViewWillEnter(async () => {const token = await storageService.getItem("token");const userInfo = await storageService.getItem("userInfo");// console.log(token, "首页token", JSON.parse(userInfo));getAreaList();getNotifyData();
});onIonViewDidEnter(() => {window.addEventListener("resize", handleResize);mitter.on("token-expired", () => {// console.log("token失效，跳转到登录页面");router.push("/login");});getChartData();
});onIonViewWillLeave(() => {window.removeEventListener("resize", handleResize);if (pieChart) {pieChart.dispose();}mitter.off("token-expired");});const handleInput = (event: Event) => {// keyWords.value = (event.target as HTMLInputElement).value;// console.log("搜索：", keyWords.value);searchList.value = [];if (keyWords.value) {getSampleInfo(keyWords.value).then((res: any) => {if (res.code === 200) {searchList.value = res.data;}})}
};const segmentChange = (event: Event) => {let val: string = (event.target as HTMLInputElement).value;selectedArea.value = areaList.value.find((item) => item.areaName == val);
};const initChart = () => {pieChart = echarts.init(inventoryStatisticsPieChart.value);let option = {title: {text: "99865",subtext: "库存总量",left: "14%",top: "center",textStyle: {fontSize: 20,},subtextStyle: {fontSize: 18,},},tooltip: {trigger: "item",},legend: {top: "center",type: "scroll",right: 0,orient: "vertical",formatter: (name: string) => {let total = 0;let target = 0;seriesData.value.forEach((item) => {total += item.value;if (item.name == name) {target = item.value;}});let percent = total ? ((target / total) * 100).toFixed(2) : 0;return `${name}  ${percent}% ${target}`;},},series: [{// name: "Access From",type: "pie",radius: ["70%", "90%"],right: "50%",avoidLabelOverlap: false,label: {show: false,position: "center",},labelLine: {show: false,},data: seriesData.value,},],};option && pieChart.setOption(option);
};const handleResize = () => {setTimeout(() => {if (pieChart) {pieChart.resize();}}, 500);
};const getAreaList = () => {getAreaSituation().then((res: any) => {if (res.code === 200) {areaList.value = res.data;selectedArea.value = areaList.value[0];}});
};const getChartData = () => {getCountrySamplePie().then((res: any) => {if (res.code === 200) {seriesData.value = res.data;initChart();}});
};const getNotifyData = () => {getNotify().then((res: any) => {if (res.code === 200) {messageList.value = res.data;}});
};</script>

参考：Vue3 mitt 组件通信 - 附完整示例