I created a sample React Js Application hosting in local server as http://localhost:3000/ . Its an NPM used Application(Node js). According to my investigation in sharepoint, if we a user need to host any Sample application it may be React , Js , Java he need to create a sppkg file within his application. If we create a sppkg file its simple to deploy it to App catalog in Sharepoint.
Anyone provide me better solution or procedure to solve this.