How to integrate Vue.js and ASP.NET Core using SPA Extension

sbzdyl 
I think you also have to change API path to production on HelloWorld.vue.

There is a code to call /api/value API.

const r = await fetch('/api/values');

After rewriting the path to '/your app name/api/values', I guess you can see a correct page on IIS.

But it is not good approach, I have updated the github repo(https://github.com/runceel/VueJsAndAspNetCore) to use .NET Core 3.1, latest Vue CLI, and adding a few changes easy to deploy to IIS.

Could you try following steps?

1. Clone the repo
2. Change publicPath on vue.config.js like following:
   

   module.exports = {
       publicPath: process.env.NODE_ENV === 'production'
           ? '/your app name/'
           : '/'
   }

3. Change an API endpoint path on .env.production like following
   

   VUE_APP_APIPATH=/your app name/api/values

4. dotnet publish -c Release
5. Copy all files that are at publish folder to your IIS app folder.
6. access to 'http://localhost/your app name'

After that you can see the page:

I hope you will get to same result!