While setting up dev environment (Laravel 8 + React ) I noticed that public/js/app.js is missing after running npm run dev command.

I ran npm run production and app.js is generated properly. Then removed the app.js and tried npm run dev again, the app.js is removed.

The below is my web.mix. My Node version is V16.12 on a windows 10 OS

    mix.js("resources/js/app.js", "public/js")
    .react()
    .sass("resources/sass/app.scss", "public/css");
   
mix.combine(
    [
        "public/admin/vendors/css/vendors.min.css",
        "public/admin/vendors/css/calendars/fullcalendar.min.css",
         "public/admin/vendors/css/extensions/toastr.min.css",
        "public/admin/vendors/css/forms/select/select2.min.css",
        "public/admin/vendors/css/pickers/flatpickr/flatpickr.min.css",
        "public/admin/css/bootstrap.min.css",
        "public/admin/css/bootstrap-extended.min.css",
        "public/admin/css/colors.min.css",
        "public/admin/css/components.min.css",
        "public/admin/css/themes/dark-layout.min.css",
        "public/admin/css/themes/bordered-layout.min.css",
        "public/admin/css/themes/semi-dark-layout.min.css",
        "public/admin/css/core/menu/menu-types/vertical-menu.min.css",
        "public/admin/css/pages/app-calendar.min.css",
        "public/admin/css/pages/dashboard-ecommerce.min.css",
         "public/admin/css/plugins/extensions/ext-component-toastr.min.css"
    ],
    "public/css/app.css"
);

What am I missing? Thanks in advance.