Fix TS transpile in CLI

[frandiox]

It looks like something changed in Remix and remixConfig.tsconfigPath now returns the jsconfig.json path when present instead of undefined like before (I think?). We were using that to detect if the project was TS or JS.

This PR fixes that issue and also replaces typescript with @babel/core + @babel/preset-typescript, which is 30MB smaller.

[blittle]

🙌

[wizardlyhel]

Trying to understand the difference between typescript and babel package.

https://www.typescriptlang.org/docs/handbook/babel-with-typescript.html

In addition to that, Babel cannot create .d.ts files for your TypeScript which can make it harder to work with your project if it is a library.

Would this be a problem for us with our other library packages? (ie. hydrogen-react, hydrogen)

[frandiox]

Would this be a problem for us with our other library packages? (ie. hydrogen-react, hydrogen)

No, Babel would only be used for project scaffolding and generating route files. E.g. you choose any combination of options in the init flow for a new project, we generate that in TS and then we transpile it to JS if that's what you chose. When doing that, we don't need to generate .d.ts for each generated .jsx, because we just want to drop types.

[frandiox]

So at the end I'm reverting to TS again and just keeping this PR to fix the original issue and a minor refactor of unnecessary things we were doing.

The reason is that it doesn't seem like Babel installs faster than TS (2.8s Babel vs 1.8s TS in my tests) even though it's smaller. Probably related to the deep tree of dependencies it has.
It's perhaps still a viable option but since it doesn't improve much of what we already have (trade a few MB with speed), let's not fix something that isn't broken I guess.