报错真正的原因export ‘default’(imported as‘Vue’) was not found in‘vue

运行npm run dev后报错：

export 'Vue' (imported as 'Vue') was not found in 'vue' 并且加载不出页面，查了很久，终于找到原因：　

报错信息：

WARNING in ./src/index.js 24:13-16
export 'Vue' (imported as 'Vue') was not found in 'vue' (possible exports: BaseTransition, BaseTransitionPropsValidators, Comment, DeprecationTypes, EffectScope, ErrorCodes, ErrorTypeStrings, Fragment, KeepAlive, ReactiveEffect, Static, Suspense, Teleport, Text, TrackOpTypes, Transition, TransitionGroup, TriggerOpTypes, VueElement, assertNumber, callWithAsyncErrorHandling

 

在index.js中，老版本的写法如下：

import Vue from "vue";
import App from './App.vue';
const vm = new Vue({
    el: '#app',
    render: h => h(App)
})

使用的Vue3.x 版本，这样在命令行运行: npm run dev  始终报错:  WARNING in ./src/index.js 24:13-16
export 'Vue' (imported as 'Vue') was not found in 'vue' 

问题原因是  导入Vue的方式没按Vue3.X 的新特性书写，应该如下：

import { createApp } from 'vue';

import App from './App.vue';

 

createApp(App).mount('#app')

再重新打包 npm run dev

完美解决。