vue3如何自定义js文件(插件或配置)

export default {
  install: (app) => {
  }
 }

// TencentCaptcha.js
import Vue from 'vue';
const appId = '*********';
Vue.prototype.$txCaptcha = (cb) => {
  const t = new window.TencentCaptcha(appId, (rsp) => {
    t.destroy();
    cb(rsp);
  }, {});
  t.show();
};
// main.js
import './config/TencentCaptcha';

export default {
// ...
methods:{
    getCode () {
        this.$txCaptcha((res) => {
            this.txResult = res;
        });
    }
}
}

// TencentCaptcha.js
const appId = '*********';
export default {
  install: (app) => {
    const Vue = app;
    Vue.config.globalProperties.$txCaptcha = (cb) => {
      const t = new window.TencentCaptcha(appId, (rsp) => {
        t.destroy();
        cb(rsp);
      }, {});
      t.show();
    };
  },
};
// main.js
import { createApp } from 'vue';
import App from './App.vue';
import txCaptcha from './config/TencentCaptcha';
createApp(App).use(txCaptcha)

<script setup lang="ts">
import {getCurrentInstance} from 'vue'
getCurrentInstance().appContext.config.globalProperties.$txCaptcha((res) => {
    this.txResult = res;
});
</script>

export default{
    install(Vue){
        var tpl;
        // 弹出框
        Vue.prototype.showAlter = (title,msg) =>{
            var alterTpl = Vue.extend({     // 1、创建构造器，定义好提示信息的模板
                    template: '<div id="bg">'
                         + '<div class="jfalter">'
                         + '<div class="jfalter-title" id="title">'+ title +'</div>'
                         + '<div class="jfalter-msg" id="message">'+ msg +'</div>'
                         + '<div class="jfalter-btn" id="sureBtn" v-on:click="hidealter">确定</div>'
                         + '</div></div>'
            });
            tpl = new alterTpl().$mount().$el;  // 2、创建实例，挂载到文档以后的地方
            document.body.appendChild(tpl);  
        }
        Vue.mixin({
          methods: {
            hideAlter: function () {
              document.body.removeChild(tpl);
            }
          }
        })
    }
}

import jFAltre from '../../assets/jfAletr.js';
import Vue from 'vue';
Vue.use(jFAltre);

this.showAlter('提示','服务器请求失败');