kanel VS openapi-typescript-codegen

I'll just quickly plug Kanel (https://github.com/kristiandupont/kanel) which I use to generate Typescript types from a Postgres database. I agree with the author to think migrations-first, though I prefer to write them in SQL to ensure I can utilize all the powerful features that Postgres has to offer.

With it, I only get types for the tables and views etc., so any join will be untyped if done client-side. This is still a big win in my opinion, and I much prefer it to normal ORM's.

I made a tool that generates Typescript types out of a live Postgres database. I've had a request for Kysely support (https://github.com/kristiandupont/kanel/issues/273), but I more or less forgot about it. I would love to hear if that would be helpful.

There are tools that will generate typescript types from a database. I made one for Postgres. But it also works at "compile time", i.e. it doesn't look at a live database. I am not sure if that is what you are asking?

That's interesting. I use Knex a lot and I agree that it's very easy to end up just writing what is basically an ORM on the spot. I haven't quite decided if I think it's a real problem though.

I created and use Kanel (https://github.com/kristiandupont/kanel) to generate Typescript types from my Postgres database which helps a lot. Knex itself has some attempt at type safety but it gets confused quite quickly, so that's where it's tempting to override things.

Interesting. Someone asked me if I supported it in Kanel. At the time it was hard to extend Kanel and then I just forgot but perhaps I should take another look at it. I am not exactly overwhelmed with the types that Knex offers even though it does make an honest attempt.

I have so far found: - kanel https://github.com/kristiandupont/kanel - and pg-to-ts https://github.com/danvk/pg-to-ts

I’ve written before about the way I let the Postgres schema act as the source of truth by generating types with Kanel (assisted by Schemalint). In addition to this, I mention a homemade framework that sort of resembles a server-side Redux. This gives me typesafe database queries that are automatically reflected all the way to the frontend. I am frequently asked to make it open source and that is still the plan. I just need to untangle it from the Submotion source code which just never seems to be high enough priority. I promise I will get around to it :-)

We are using Kanel[1] for this right now — is there an advantage to using this instead?

[1]: https://github.com/kristiandupont/kanel

Sure. I've been using this lib https://github.com/kristiandupont/kanel to get types from my pg database and it makes it a breeze to use raw sql + ts.

I’d also add that if you use Typescript with an OpenAPI client generator (https://github.com/ferdikoomen/openapi-typescript-codegen) it can immensely alleviate some of the biggest pain points of seperate backend and front-end. It always used to be a major pain in the ass with the amount of overhead an API change would incur - updating documentation, postman, constant communication between backend and front-end devs, etc. Now I just npm run generate, I see new API changes in my Git client and Typescript errors for code that needs updating.

Also, using a library like Tanstack Query or Rdtk Query can almost completely eliminate manual state management, and kinda makes the whole development experience feel almost like SSR.

I have been in love with Loopback.io since v2 even though it was a bit of a rollercoaster.. Loopback v4 is a beautiful library. Its been around longer than nestjs but that's the easiest thing to compare it too. I recently have been creating lb4 servers that interface nextjs and react native clients. Initially, I identify my entities and use cases that I want to build. I then use the lb4 cli to auto generate models, relations, controllers, datasources, interceptors (add logic on methods/classes). I can start testing them with the OpenAPI explorer. With the openapi-typescript-codegen library I can generate services from my lb4 OpenAPI spec that I can use on the client side. From there, you can really query data easily with the loopback filter (which can be used on the client too). I initially started doing this with angular1/2+ but its been pleasant using many clients. Even though I have been leveraging it for years in production, I am still learning and exploring. There are many other awesome things I can expand on or explain if you are interested!

https://loopback.io/doc/en/lb4/

https://github.com/ferdikoomen/openapi-typescript-codegen/tr...

In our current project with a TS frontend and Python backend, we use an OpenAPI schema as the source of truth and openapi-typescript-codegen [0] to interface with it on the client side. While not perfect, it provides a very nice interface to our API with request/response typings.

I also wrote a 10-line mock API wrapper that you can call as mockApi((request) => response), and it will type-check that your mock function implements the API correctly.

[0]: https://github.com/ferdikoomen/openapi-typescript-codegen

Second step is to generate typescript types from the backend's spec. You can use a library like this.

openapi-typescript-codegen Generates a Typescript client with interfaces from an OpenAPI spec.

I'm not familiar with all the options openapi-generator has. I tried it awhile ago and found it quite buggy, and more of a pain to run, especially if you're not already doing Java development. I ended up preferring OpenAPI Typescript Codegen, which is written in Typescript. One option it has which would solve the problem you're running into here, is that you can tell it to use union types instead of enums. So your interfaces would be generated as

I'm currently working on two separate projects, the first is a Django project with DRF and I codegen with drf-spectacular [1] and openapi-typescript-codegen [2]. The other project also uses Django, with the API through Hasura and codegen with graphql-codegen [3]. In both of these cases I've been able to largely avoid duplicating my models clientside, or at least it isn't manual.

1: https://github.com/ferdikoomen/openapi-typescript-codegen

2: https://drf-spectacular.readthedocs.io/en/latest/

3: https://github.com/dotansimha/graphql-code-generator

For typescript client code generation, I typically use something like openapi-typescript-codegen, but there are a lot more generators (like the openapi-generator project) that are imperfect in their own ways, I'm sure you can find one that works for you.