rangle/example-chained-libraries: An example of how libraries can be chained using npm workspaces and typescript · GitHub

I created from scratch a monorepo using npm workspaces containing: @my/ui a simple vanilla TS, vite-compiled module @my/wrapper a simple vanilla TS module, also vite-compiled, depending on @my/ui my-application a simple angular application, utilizing @my/wrapper

I declared a type on @my/ui called ThingType that is the input type for the function wrapThing, declared in @my/wrapper

I proceeded then to import this wrapper function in my-application -- that has a dependency on @my/wrapper but not on @my/ui

Results:

• exported function works fine
• exported function has the proper types of the input identified and constrained (i.e.: I have an error if I don’t add all the necessary fields)
• exported function autocompletes the fields of the ThingType in my-application

The setup works on both node 20 and node 18

I developed the example further along by creating two layers of type validation:

• types on @my/ui will be automatically picked up by @my/wrapper and my-application (also from @my/wrapper to my-application) from source. This means, the second you change the type in the library, the application will show you a typescript error.
• the build, however, will not pick types automatically from source. It will only break the build of my-application when you build the library — because builds are looking at dist/index.d.ts

I think this addresses all the constraints we have on the way the monorepo is supposed to behave, and it even solves the type export issue by separating IDE issues from build issues.