title: Best way to integrate webpack builds with ASP.NET Core 3.0?
body: <p>I'm upgrading my ASP.NET Core app to V3, and using Visual Studio 2019 for development / debugging. The process has been smooth except for this:</p>
  
  <pre><code>public void Configure(…..
                  app.UseWebpackDevMiddleware(new WebpackDevMiddlewareOptions
                  {
                      HotModuleReplacement = false,
                      ReactHotModuleReplacement = false
                  });
  </code></pre>
  
  <p>UseWebpackDevMiddleware is no more: <a href="https://github.com/aspnet/AspNetCore/issues/12890" rel="noreferrer">https://github.com/aspnet/AspNetCore/issues/12890</a> .</p>
  
  <p>I'm now looking to understand the best way to have VS run webpack every time I debug, ideally only on JS code that has changed. This was the value I was getting from <code>UseWebpackDevMiddleware</code>. My app is a React app, and it seems like there is some new replacement for this if your app was started from CreateReactApp, but mine was not.  (I believe apps that stated from this but then separated are called "ejected.") Is it somehow possible for me to still take advantage of whatever that facility is, even though my app does not leverage CreateReactApp? Also, what is the role of CreateReactApp after it bootstraps your new React application? I imagined it would be only used for inflating template code at the first go.</p>
  
  <p>What is the role of Microsoft.AspNetCore.SpaServices.Extensions in all of this?</p>
  
  <p>I don't need hot module replacement; I don't need server side prerendering. I'm really just trying to understand how to get my JS to transparently build (via Webpack) as part of my debugging process. Is this something that I could hook into MSBuild for? I imagine others are going to face the same question as they upgrade. </p>
  
  <p>Thanks for any suggestions.</p>