isopod VS typescript-json-schema

Tried it[0], worked reasonably well. Be prepared for strong opposition from traditional “devops” folks “who don’t mind yaml” and will drag everyone down.

[0] - https://github.com/cruise-automation/isopod

I like Cue and Jsonnet and Starlark and so on. But all of these have very low mindshare (though Starlark has the most momentum thanks to Bazel), and who knows if they will be dead by next year.

Being an early adopter is difficult both in terms of the immaturity of the tooling — Cue, for example, only has a Go implementation at the moment — and in terms of the risk of betting on an evolutionary dead end, which can cause a lot of unnecessary churn when you want to standardize on something across an entire organization.

As a concrete example, I'd love to replace Kubernetes's use of YAML with something like the above. But the tooling is immature, and almost nobody is using any of it. For example, there's Isopod [1], which is a nice-looking tool to use Starlark with Kubernetes. But it might go the same way as Ksonnet.

[1] https://github.com/cruise-automation/isopod

Typescript to JSON Schema

For anyone using both TypeScript and JSON schemas, but wanting to use TypeScript as the source of truth, I highly recommend the following library: [ts-json-schema-generator](https://github.com/YousefED/typescript-json-schema).

It does exactly what it says in the box: turns your TypeScript `types` / `interface` into machine-readable JSON schemas.

The library has a few open issues (does not deal well with some edge cases of composing Omit<> on sum types, and does not support dynamic (const) keys), but compared to manually writing JSON schemas, it's been amazing!

There are a bunch of tools to generate JSON-schema from a TS codebase, ie https://github.com/YousefED/typescript-json-schema

Now that cool thing we wanted to do? This library does exactly that!

> For more complex cases I find myself wishing I could just turn Typescript into some kind of schema validation for JSON.

Not sure if this is what you're looking for, and whether it's powerful and expressive enough for your use case, but you can use typescript-json-schema¹ for this, and validate with eg ajv.

¹https://github.com/YousefED/typescript-json-schema

Use https://github.com/YousefED/typescript-json-schema to go from TS -> json schema

For what it's worth, thanks to TypeScript transformers (a feature baked into the compiler), one can create a transformer library that verifies an object is valid for any TypeScript type and conveys that information to the typechecker. And indeed, it's already been made. It allows to parse unknown into a given T. This is nice, because one can generate a JSON schema out of a TS type, for other languages/codebases to integrate safely.

This is why I originally started a project to convert ts to json schema; https://github.com/YousefED/typescript-json-schema (and also check out a good alternative https://github.com/vega/ts-json-schema-generator)

Typescript JSON schema