There are plenty of projects that do the same for TypeScript (e.g. https://github.com/typescript-rtti/typescript-rtti) and plenty that support some kind of runtime reflection, and overall emitting TS type information at compile time in some readable format is a pretty trivial problem to solve. The complicated part is on the other side – what do you do with this information? How do you get JavaScript engines to understand it?
So then...exactly how it is done today? TypeScript provides an API to get type info at compile time. Libraries write plugins to consume this type info and use it for runtime and custom validation. What changes in this new world?
> So then...exactly how it is done today? TypeScript provides an API to get type info at compile time.
That's exactly it, it doesn't. That project you linked (typescript-rtti) mentions in the README that you must install and use it via ttypescript, a typescript wrapper that patches the compilation process to expose compilation details to plugins. Except that plugin API is unofficial and changes break the ecosystem built on it. For example, ttypescript doesn't work for TS 5 and the dev doesn't want to spend time on it. ts-patch has stepped in to provide a source transformer API for TS 5.
There's no way I can recommend libraries like typescript-rtti in commercial projects until something changes. I hope the ts-patch folks don't burn out.
