No transpilation on IIS production server - reactjs.net

Question

First off, a lot of this technology is new to me, so I apologize for the noob question. Also, this is my first post to SO (after years of reading), so forgive the formatting.
I have a web application that I am running via MSVS 2017. I am writing my front end with React.js. After installing the appropriate packages via nuget, I have something that works when I run both the debug and release versions on my local dev machine (using iisexpress).
However, after I commit my source changes, and it gets pushed to the test server (IIS), the app runs fine. But, the JSX files that are returned from the test server are not transpiled. I just get the raw JSX file. Whereas, on my local machine, the returned file is transpiled.
I have a ReactConfig.cs file with a single static Configure method, where I have a call to add my JSX file via ReactSiteConfiguration.Configuration.AddScript, but that appears to be unnecessary because I still get a transpiled result even when it is commented out. At the top of my ReactConfig.cs file I have seomthing similar to:
[assembly: webActivatorEx.PreApplicationStartMethod(typeof(MyApp.Api.Controllers.MyController), "AutoMapperStart")]
So, then I am left with the question of how is the transpiling occuring on my dev machine, but not the deployment machine.
In my web.config file, I have tried both:
<httpHandlers>
<add verb="GET" path="*.jsx" type="React.Web.BabelHandlerFactory, React.Web" />
</httpHandlers>
and
<remove name="Babel" /><add name="Babel" verb="GET" path="*.jsx" type="React.Web.BabelHandlerFactory, React.Web" preCondition="integratedMode" /></handlers>
But neither seems to make a difference on the deployed server.
If anyone has suggestions of what I should look at next, it would be greatly appreciated.
Update:
I notice the relevant item that is allowing my dev environment to do the transpilation is the second code section above in my web.config file. However, that I don't see the same lines on the server. Are web.config file typically 'hand edited' per deployment, perhaps?

Answer 1

So, here is what I eventually figured out that worked for me.
First, yes, the web.config file is deployed with as a template. And then hand configured as necessary.
Second, and more importantly, there are two parts to getting the server to render JSX to pure JS.
I needed the following in the web.config file:
<system.webServer>
<handlers>
<remove name="Babel" />
<add name="Babel" verb="GET" path="*.jsx"
type="React.Web.BabelHandlerFactory, React.Web"
preCondition="integratedMode"/>
</handlers>
</system.webServer>
And finally, in the assemblyBinding section:
<dependentAssembly>
<assemblyIdentity name="JavaScriptEngineSwitcher.Core" publicKeyToken="c608b2a8cc9e4472" culture="neutral" />
<bindingRedirect oldVersion="0.0.0.0-2.4.9.0" newVersion="2.4.9.0" />
</dependentAssembly>