One remaining annoyance is that when overriding the json it is removing all comments from the file.

This isn't too big of a deal when using source control -- you could only stage the lines you care about.

If you can figure something out, please send PR.

@Timer, @brunolemos. Just a heads up that we're missing part of how TypeScript reads in tsconfig.json. If you take a look at my #5519 PR, you'll see how I was also using ts.parseJsonConfigFileContent() which takes care of resolving things like "extends": "./tsconfig.other.json".

Let me know if you want me to make a PR to add that step!

Here's a reference from ts-jest as an example: https://github.com/kulshekhar/ts-jest/blob/13cc4c9b0136030d0aa52dcbe3efb65c48012d70/src/config/config-set.ts#L654

Sure, send a PR please.