运行vue项目时显示报错信息：

 WARNING  Compiled with 46 warnings                                                                                  上午10:28:45

 warning  in ./node_modules/vue-router/dist/vue-router.esm-bundler.js

1848:4-15 "export 'onUnmounted' was not found in 'vue'
 warning  in ./node_modules/vue-router/dist/vue-router.esm-bundler.js

3387:42-50 "export 'reactive' was not found in 'vue'

 warning  in ./node_modules/vue-router/dist/vue-router.esm-bundler.js

3443:11-17 "export 'inject' was not found in 'vue'

3450:11-17 "export 'inject' was not found in 'vue'

 warning  in ./src/router/index.js

6:8-14 "export 'default' (imported as 'Router') was not found in 'vue-router'

 warning  in ./src/router/index.js

8:19-25 "export 'default' (imported as 'Router') was not found in 'vue-router'

vue-router版本号过高。将vue-router回退版本

   执行命令:npm i vue-router@3.2.0