Example config your Laravel project with two builds (public and admin)

1. Create Laravel Project

   laravel new my-project
   cd my-project
   # remove existing frontend scaffold
   rm -rf package.json webpack.mix.js yarn.lock resources/js resources/sass public/js public/css

2. Create a Vue CLI 4 project in the Laravel '/resources/frontend/'

   cd resources/frontend
   vue create app
   #and (if you need admin build)
   vue create admin

3. Configure Vue CLI 4 project

   Create /resources/frontend/app/vue.config.js:

   module.exports = {
    devServer: {
      proxy: 'https://laravel.test'
    },
   
     // output built static files to Laravel's public dir.
     // note the "build" script in package.json needs to be modified as well.
     outputDir: '../../../public/assets/app',
   
     publicPath: process.env.NODE_ENV === 'production'
       ? '/assets/app/'
       : '/',
   
     // modify the location of the generated HTML file.
     indexPath: process.env.NODE_ENV === 'production'
       ? '../../../resources/views/app.blade.php'
       : 'index.html'
   }

   Edit /resources/frontend/app/package.json

   "scripts": {
     "serve": "vue-cli-service serve",
   - "build": "vue-cli-service build",
   + "build": "rm -rf ../../../public/assets/app/{js,css,img} && vue-cli-service build --no-clean",
     "lint": "vue-cli-service lint"
   },

   and (if you need admin build)

   Create /resources/frontend/admin/vue.config.js:

   module.exports = {
     // proxy API requests to Valet during development
     devServer: {
       proxy: 'https://laravel.test/admin'
     },
   
     // output built static files to Laravel's public dir.
     // note the "build" script in package.json needs to be modified as well.
     outputDir: '../../../public/assets/admin',
   
     publicPath: process.env.NODE_ENV === 'production'
       ? '/assets/admin/'
       : '/admin',
   
     // modify the location of the generated HTML file.
     // make sure to do this only in production.
     indexPath: process.env.NODE_ENV === 'production'
       ? '../../../resources/views/admin.blade.php'
       : 'index.html'
   }

   Edit /resources/frontend/admin/package.json

   "scripts": {
     "serve": "vue-cli-service serve",
   - "build": "vue-cli-service build",
   + "build": "rm -rf ../../../public/assets/admin/{js,css,img} && vue-cli-service build --no-clean",
     "lint": "vue-cli-service lint"
   },

4. Configure Laravel routes for SPA.

   routes/web.php

   <?php
   // For admin application
   Route::get('/admin{any}', 'FrontendController@admin')->where('any', '.*');
   // For public application
   Route::any('/{any}', 'FrontendController@app')->where('any', '^(?!api).*$');

   app/Http/Controllers/FrontendController.php

   <?php
   namespace App\Http\Controllers;
   use Illuminate\Http\Request;
   
   class FrontendController extends Controller
   {
       // For admin application
       public function admin()
       {
           return view('admin');
       }
       // For public application
       public function app()
       {
           return view('app');
       }
   }

5. Change base: process.env.BASE_URL in router.js for correct Vue Router

   // For App
   base: '/',
   // For Admin
   base: '/admin/',

6. Add package.json in root (if you want use yarn run in root)

   {
     "name": "laravel",
     "version": "0.2.0",
     "private": true,
     "scripts": {
       // For public application
       "serve:app": "cd resources/frontend/app && yarn run serve",
       "build:app": "cd resources/frontend/app && yarn run build",
       "lint:app": "cd resources/frontend/app && yarn run lint",
       "test:app": "cd resources/frontend/app && yarn run test:unit",
       // For admin application
       "serve:admin": "cd resources/frontend/admin && yarn run serve",
       "build:admin": "cd resources/frontend/admin && yarn run build",
       "lint:admin": "cd resources/frontend/admin && yarn run lint",
       "test:admin": "cd resources/frontend/admin && yarn run test:unit"
     }
   }