node-starter | Runtime Evironment library

You can use babel. I used following babel library in node project and every ES6 features work properly.

Sounds like your compiler (TSC) config file may be up a level from where you want the transpiler to begin the linking process. Can you try pushing it down a level and let us know what happens?

Hope this helps.

Only ports 80 and 443 are open for Web Apps. You should change the listen port to process.env.PORT.

Typescript is a (or rather, a superset of) language - not a runtime. It is the equivalent of Javascript except it needs to be compiled to run on the Node.js runtime.

You can write the backend with Typescript if you want, and then run it through ts-node, or just compile down to ES6 via tsc and then run it with standard Node (v8+ is recommended). This is what I do with many projects. It is still "node code", it just has all the benefits (and gimmicks) or Typescript.

1. correct. You can see why it's src/ to dist/ and a few other details regarding TypeScript-to-JavaScript in tsconfig.json (TypeScript expects this file to exist and declare all these things - see here for details).
2. wrong, but it's kind of tricky. Node here isn't run directly since it doesn't declare an entry point in package.json. Instead, this file declares a script.start command that is called when typing directly npm start, which executes npm run serve, which is declared to execute node dist/server.js. Conclusion: your entry point is server, not app.
3. wrong: __dirname is a variable always available in a file, and it contains - at runtime - the path of this file's directory. Since your file in src/ is converted to a file in dist/ and executed there, the actual files being served are in dist/public. Have a look at package.json for its command build (hint: there's something about copying static assets, and another about building Sass).
4. wrong as per point 3, correct otherwise.

Now you should have the answer to your question. ;)

This has probably been answered more than a couple of times so I will be brief.

A Type or type is like a blue-print for an object. Best to explain it with a example:

If you have a type called Animal:

mongoose is indeed type casting, albeit the old syntax. The more current form would be (mongoose as any).Promise = bluebird. It means that you take the reference to mongoose and ignore its actual type, and treat it as any.

This prevents compile-time errors from type mismatches with mongoose.

In general, you should not cast to any, and you should look into why that is required of you in this case and see if you can avoid it.

I think it is a good practice to have everything in an organized way and not in a single file.

In this case server.js is used to start the web server where we can stipulate the port and other configurations, and in the app.js file is where the routes and middleware are added to the express application.

So we can continue having everything in different layers where for example we can have the detail of our routes with their respective controllers, another layer where the data repository is stipulated, etc, etc.

In short the idea of having this is order and organization of the code, when making changes or maintenance a clean code makes things easier.

Per the API docs, req, and res hold a reference of the Express app instance.

https://expressjs.com/en/4x/api.html#req.app

https://expressjs.com/en/4x/api.html#res.app