Experiment with allowing absolute paths for imports in core

[mjbvz]

For #236644

Quickly hacked this together to allow #/vs/ absolute imports. This only works for dev right now

@bpasero @jrieken Let me know if this is something we would like to look into further

[bpasero]

@mjbvz hm interesting, but:

• how does this work for auto imports that TS generates, they would be relative, no?
• not a very big fan of a leading # in imports, I prefer the relative imports in this case
• we also need to support VS Code for web, where we have a CSS dev service as well

[jrieken]

@mjbvz Where does the #<somepath> syntax come from? Is that some JS/browser standard?

[mjbvz]

Good questions @bpasero and @jrieken :

• TS will emit the path as written (#vs/...). So our runtime environments also need to handle understand this style of import. That's why the changes in setupDevImportMaps and the package.json are also needed

• The # is a node convention. As far as I know browsers do not have a similar convention. Starting imports with # makes it clear that these paths are not for an external module. Here's the relevant docs: https://nodejs.org/api/packages.html#subpath-imports

• I think that already should work but let me double check

[jrieken]

The # is a node convention. As far as I know browsers do not have a similar convention.

I am really skeptical about that. We have just left the custom AMD world behind us and use plain, standard JS now. So, this feels like buying into the next custom thing