re-typescript

An opinionated attempt at finally solving typescript interop for ReasonML / OCaml.

Why

I am maintaining a package of automatically generated bindings for Material UI. Generating these bindings is becoming more and more frustrating, as the complexity of the original package grows and tools that wish to cover everything begin to break down. this leads to more and more types missing on each cycle and precious time spent on recovering them by adjusting the type extraction process. Right now the generator uses a library which converts typescript into a json-schema which then get's analyzed & parsed into reason code. I believe that these tools want to cover too many use cases in order to be effective. So I'm setting out to simplify this process and maybe provide an effective way of generalizing type mapping between reason and typescript.

Quite ambitious. We'll see.

Idea

re-typescript implements it's own lexer / parser to analyse typescript declaration files specifically. It purposefully does not want to get into tracking inferred types through *.ts files. It only extracts cleanly defined types as best as it can.

I am not sure about how to handle unparseable code yet. I believe a best approximation appraoch will be best, where it will gracefully end the traversal by just injecting an abstract type of some sort, instead of failing or fully omitting a type.

re-typescript first derives a primitive AST from the tokenization process. It then decodes that AST by way of resolving references / dependencies. Finally it directly generates an ocaml AST, which allows for easy printing of both reason & ocaml. I'm composing the ast by using ocaml-migrate-parsetree, which will later allow for an easy use inside of a potential PPX.

This tool will be opinionated about a few things. Typescripts dynamic nature makes this unavoidable. I am not yet sure how the native mode will generate it's types exactly (esp. regarding unions / mixed enums). Bucklescript has great features for handling these things, like the @unboxed attribute, as well as @bs.string for externals and bs.as in records.

Playground

I will update the playground from time to time. It's not great yet, I just wanted a visual representation for now. You can see the current progress here: re-typescript

Roadmap

See projects section: re-typescript projects