@drzl/generator-pothos

Generate a Pothos schema builder from a Drizzle schema: one object type per table, each checked against the row type it came from.

Why this and not the SDL

DRZL already emits GraphQL SDL. SDL is a string: it describes a schema and cannot be extended, so a resolver written against it is checked by nothing. A Pothos builder is code, and t.exposeString('emial') is a compile error here where it silently returns undefined there. That is the whole reason to emit one.

Both generators agree exactly on which GraphQL type each column gets. The same column described two ways by two DRZL generators is worse than either description on its own.

Install

npm install -D @drzl/generator-pothos
npm install @pothos/core graphql

// drzl.config.ts
export default {
  schema: './src/db/schema.ts',
  generators: [{ kind: 'pothos', path: 'src/graphql' }],
};

Nullability is stated on every field

Pothos defaults every field to nullable, so a NOT NULL column written as a bare t.exposeString('email') reaches clients as String. The obvious fix, defaultFieldNullability: false on the builder, does not compile: that option is legal only on a builder with no type parameter, which runs in v3 compatibility. On a v4 generic, which is what a generated builder is, it types as never because there it exists only to opt into nullable. The runtime default is nullable in both shapes, so the central switch is unavailable exactly where it would help.

Every emitted field therefore says which it is, which also lets a reader see a column's nullability without knowing anything about the builder.

Scalars

Int only where declared bounds prove 32 bits, Float otherwise, since graphql-js refuses 2^31 and an unbounded integer column must not fail reads. DateTime, BigInt and JSON are registered scalars written into the emitted tree rather than pulled from a dependency. BigInt travels as a string, because JSON.stringify(1n) throws and a number loses precision past 2^53.

Stub resolvers throw rather than returning an empty array: a caller reading [] cannot tell "no rows" from "nobody wrote this yet".

Full documentation: https://use-drzl.github.io/drzl/generators/pothos

Licence

Apache-2.0. Generated output is yours under your own project's licence.