Compiling typescript path aliases to relative paths for NPM publishing?

There is a project called ttypescript that you can use for this. If you use it with the module typescript-transform-paths I beleive it will acheive what you want.

As a brief follow-up to arhnee's suggestion, it seems that as of Aug 2020, Microsoft still refuses to implement custom transformers for whatever reason, so these modules remain relevant.

So to future readers, here's how you can actually compile TS path aliases to relative paths. ttypescript is merely a transformer framework that requires a "path transformer" in order to actually convert the TS path aliases. Thus you will need to install both ttypescript and typescript-transform-paths.

npm i --save ttypescript typescript-transform-paths

Then, it's easy as just specifying usage by adding the following property to the compilerOptions object in tsconfig.json:

    "plugins": [
      { "transform": "typescript-transform-paths" }
    ]

And finally, run ttsc instead of tsc.