Author here. That's good feedback. Looks like that part of my article is a bit confusing and I've updated the phrasing a little to hopefully make it less so.
You're spot on with all of your points. The isolated declarations feature forces your code to be written in a way that creating the .d.ts files is a mere exercise of stripping syntax and can be done easily without invoking the tsc compiler.
For runtimes like Deno which support running TS natively (disclaimer: I work for Deno) you never had to care about creating .d.ts files when publishing your package to any of the Deno registries: previously /x, now JSR. In the background though we've always tried to feed the tsc compiler in Deno something like .d.ts files though as it's quicker for type checking purposes.
Author here. Agree! The whole npm ecosystem is based around npm packages shipping JS files and doing anything else would break it. I've updated the article to hopefully make it less confusing. The takeaway should definitely not to only publish TS files to npm.
I mainly work with Deno which can run TS files natively (disclaimer: I'm employed by them). This changes the parameters a little as all registries for Deno could always ships the TS sources directly. But when publishing to npm you always have to publish the JS sources to work with runtimes like Node that don't support running TS natively.
Author here. True, I think I should've worded it better. I work for Deno and it being a JS runtime that is able to run TS natively makes this less of an issue. The problem that a dependency needs a specific TS version hasn't come up so far. But that might be because Deno users tend to update to the latest version pretty frequently as we haven't done any breaking changes so far.
Author here. I should've worded that better. The recommendation is not to stop compiling TS->JS for npm users. The whole npm ecosystem is built around the assumption that you ship JS and doing anything else would break it.
In Deno (disclaimer: I work for Deno), which supports running TS natively, packaging outside of npm has always worked by shipping the TS files directly. Transpiling them down to JS files is only something you ever had to do when publishing on npm.
So far the problem that a dependency only compiles with a certain version of tsc hasn't popped up since Deno was launched. But that may have been because Deno always ships with latest TS and Deno users don't hesitate to update as we haven't done any breaking changes so far.
Author here. I should've worded that better in the article. The takeaway should not be to publish only TS sources to npm. The whole npm ecosystem is based around the assumption that you ship .js files and doing anything else would break it. I've updated the wording to hopefully make it less confusing.
Author here. Unfortunately, I think worded that a bit confusingly in the article. I'm used to working with runtimes that run TS natively and didn't have to care about .d.ts files myself for a long time. From that perspective creating them by running the tsc compiler feels like a manual step for me.
There are cases where folks write them by hand, but that's not what I had in mind when writing the article. I've rephrased that part a bit to hopefully make it less confusing.
The fact that there are developers out there that are willing to accept hour long compile times from the typescript compiler is disgusting. I’ve seen slow recursive types here and there, but you can analyze your slow types using tsc and fix them yourself.
I hope that slow typescript compiling is a niche issue for massively large/complex codebases and not a common problem.
Author here. That's a good point and maybe a matter of perspective. I've worked on projects where using tsc to generate .d.ts files took close to an hour. Even 13s would be too long in my opinion. It should be instantaneously. I guess it depends on where one's personal tolerance threshold is. I have a bit of a lower one as I easily get distracted and loose flow.
Author here. Thanks for sharing that feedback. I think I missed the mark by being so used to working with runtimes that natively run TS files, that I forgot that this is not the default for everyone. The article was mostly written from that perspective.
For Node users the isolated declaration feature won't do much other than speed up the creation of the .d.ts files a little. For runtimes that can run TS natively like Deno (disclaimer: I work for Deno) the benefit is much more apparent as you always want the original TS sources, but can generate .d.ts files on the fly for faster type checking.
