Postgres zod

[aristotelis96]

First attempt to generate Zod schemas from Postgres

This PR introduces a method for generating Zod schemas based on Postgres table definitions. It maps SQL data types to the corresponding Zod types, allowing us to easily validate our API payloads against database structure.

Usage

Just run the tool as usual, including the flag --generate-zod-schemas and the output file should contain zod schemas instead of TS types.

Limitations

Only postgres is supported in this PR.

Current Status

• This implementation may contain bugs, particularly around edge cases in SQL type mappings (e.g. composite types).
• I tested it with a fairly big and complex database but it would be nice to tests with other databases as well.
• Testing: I haven't implemented tests yet, but I plan to write some tests.

Request for Feedback

• I'd appreciate any feedback.
• If you find any bugs or edge cases that I may have missed, please point them out.

Closes #86.

[aristotelis96]

Rebased, added tests, formatted and fixed small issues.

[hazirmagron]

Why not merge @RobinBlomberg ?

[RobinBlomberg]

Hey, thanks for the PR!

Per my comment here, I will not add specific support for Zod into kysely-codegen (nor favor it over Joi, Yup, Ajv, Valibot, JSON Schema or any other schema library people might use).

With that said, I am almost done with a new kysely-codegen version that will make it possible to add a custom codegen through a .kysely-codegenrc.(ts|js) file. It will likely be released within ~1 week. Then it should be possible to do something like:

import { zodSerializer } from 'some-custom-kysely-codegen-serializer';

export default {
  camelCase: true,
  serializer: zodSerializer,
  url: 'postgres://user:password@localhost:5433/database',
};

So I very much welcome alternative codegens as soon as that has been released, but I don't want to maintain a possibly infinite list of codegens in the kysely-codegen core.