tsdx ignores tsconfig.json "extends" keyword

[justingrant]

Current Behavior

There's an extends feature in tsconfig which allows configuration inheritance across multiple tsconfig files. This however isn't recognized in tsdx, which parses tsconfig here:

tsdx/src/createRollupConfig.ts

Lines 46 to 49 in 4f6de10

	let tsconfigJSON;
	try {
	tsconfigJSON = await fs.readJSON(paths.tsconfigJson);
	} catch (e) {}

The JSON object is used as-is, instead of drilling up to resolve parent config.

Expected behavior

tsdx should process extends just like tsc does.

Suggested solution(s)

In a quick look through TypeScript's source code I couldn't find the place where extends is handled, but it's possible that TypeScript's exported tsconfig parsing functions might handle extends for us automatically. See https://github.com/microsoft/TypeScript/blob/760393f893358a462b00eef7e8fb92342b0f71ad/lib/typescript.d.ts#L3639-L3647 what what TS offers in its API. The implementation is here: https://github.com/Microsoft/TypeScript/blob/6487d1ffe0d903b1e55a187ddeb973fe0d445a2f/src/compiler/parser.ts#L717

Additional context

This problem is similar to #483 in that both this issue and that one are caused by parsing tsconfig differently than tsc does.

Your environment

Software	Version(s)
TSDX	[email protected]
TypeScript	[email protected]
Browser	n/a (this is a build issue)
npm/Yarn	[email protected]
Node	v12.13.1
Operating System	MacOS Catalina 10.15.2

[swyxio]

great qtn. we'll probably want to handle this.

[ncphillips]

👍 this would be great for typescript monorepos. Some of the tinacms packages use tsdx for builds. Ideally most of the config would be in the root tsconfig.json with the occasional special case in the package's.

[justingrant]

Echoing @ncphillips, I originally ended up here at tsdx because my project depends on the https://github.com/reach/reach-ui monorepo that uses tsdx and uses extends in tsconfig.json. I wanted to help reach-ui get its declaration maps fixed in its monorepo. But without extends support any fix will involve making changes to ~20 different packages' tsconfig.json files, which is not ideal.

Luckily the only rollup settings pulled direct from JSON by tsdx are esModules (which doesn't actually use tsconfig because of #469) and useTsconfigDeclarationDir (once #468 is merged). In other words, currently this issue has no impact... but it will have impact once those other two issues are resolved.

[swyxio]

anyone want to tackle this?

[agilgur5]

anyone want to tackle this?

Oh, I already did hah. @justingrant said he didn't have time for this in #483 (comment) so I made the solution myself (see above reference). Still need to add a test for the extends case, hence the draft, but will do that in a day or few as I have to focus on some other things

[swyxio]

ok. @agilgur5 we're piling up quite a few PR's for jared to review, lets slow down so that we dont swamp him with too much stuff.

[jaredpalmer]

Hrmmm. I thought this worked? Maybe a false positive. Let’s fix

[agilgur5]

Hrmmm. I thought this worked? Maybe a false positive. Let’s fix

@jaredpalmer see #484 (comment) . #483 also has a more detailed description. This is specifically for TSDX-specific options like esModuleInterop. It is already handled by rollup-plugin-typescript2 for the most part, but some tsconfig options affect TSDX too.
Also already made a PR yesterday as I mentioned and referenced above (#489)

[agilgur5]

ok. @agilgur5 we're piling up quite a few PR's for jared to review, lets slow down so that we dont swamp him with too much stuff.

@sw-yx think that might be the first time I've been asked to contribute less 🤔 🤔 🤔

[swyxio]

i mean i just want to keep it manageable for jared. its not my name on the repo heheh

[ncphillips]

On the mention of contributing less, I'm just going to leave this reference to theory of constraints here 😄

[agilgur5]

@jessekrubin are you sure you were facing this issue? As written above a few times, currently this only affects the esModuleInterop setting, and that actually has a bug (#469), so this issue currently has 0 impact on anything (it only has future impact like #468 )

[agilgur5]

Repeating here from #483 :

Merged in #489 as I'm now a collaborator. Turns out that ts.parseJsonConfigFileContent is needed to parse extends, but ts.readConfigFile is enough for comments and commas. These are not remotely well documented, so I had to search around other repos to figure out how to do this simply and properly. Can read the PR comments for what I searched through