Fix composite project setup

[MattiasBuelens]

Another attempt! 😛

• Make main the "root project", i.e. run tsc -b src/main (instead of tsc -b)
• Specify rootDir and outDir once in the top-level shared tsconfig
• Specify the project references in main because they are not inherited through extends, see references are not inherited in tsconfig.json microsoft/TypeScript#27098

That seems to fix all build-related errors. There are still type errors because of microsoft/TypeScript#14877, but you could work around that with something like self as DedicatedWorkerGlobalScope.

[jakearchibald]

@MattiasBuelens thank you! I think this is pretty much as good as it gets.

[jakearchibald]

I'll write this up at SO tomorrow and credit you.

[MattiasBuelens]

Sweet! I'm Mattias Buelens on SO, in case you want to @ me. 🙂