feat: add groupBySchema to group types and enums under a namespace

[arthurfiorette]

I didn't need to fix any test after adding this feature, this means that everything kept running exactly as before when groupBySchema is not true.

We are using this plugin in a giant schema (100+ tables under 18 schemas) where some of them have the same or similar names, which is very hard to spot visually which schema a imported type comes from.

This plugin simply adds all enums and models under a ts.ModuleDeclaration respective to their schema and fixes types references to it. Making much more easier to work with schemas, the same visually/architecturally as the thinking why schemas as written like schema.model inside SQL.

generator kysely {
    provider        = "node ./dist/bin.js"
    previewFeatures = ["multiSchema"]
    groupBySchema   = true
}

datasource db {
    provider = "postgresql"
    schemas  = ["mammals", "birds", "world"]
    url      = env("TEST_DATABASE_URL")
}

model Elephant {
    id      Int     @id
    name    String
    ability Ability @default(WALK)
    color   Color

    @@map("elephants")
    @@schema("mammals")
}

model Eagle {
    id      Int     @id
    name    String
    ability Ability @default(FLY)

    @@map("eagles")
    @@schema("birds")
}

enum Ability {
    FLY
    WALK

    @@schema("world")
}

enum Color {
    GRAY
    PINK

    @@schema("mammals")
}

Now generates:

export namespace World {
  export const Ability = {
    FLY: "FLY",
    WALK: "WALK",
  } as const;
  export type Ability = (typeof Ability)[keyof typeof Ability];
}
export namespace Mammals {
  export const Color = {
    GRAY: "GRAY",
    PINK: "PINK",
  } as const;
  export type Color = (typeof Color)[keyof typeof Color];
  export type Elephant = {
    id: number;
    name: string;
    ability: Generated<World.Ability>;
    color: Mammals.Color;
  };
}
export namespace Birds {
  export type Eagle = {
    id: number;
    name: string;
    ability: Generated<World.Ability>;
  };
}
export type DB = {
  "birds.eagles": Birds.Eagle;
  "mammals.elephants": Mammals.Elephant;
};

Instead of putting everything globally as previously:

export const Ability = {
  FLY: "FLY",
  WALK: "WALK",
} as const;
export type Ability = (typeof Ability)[keyof typeof Ability];
export const Color = {
  GRAY: "GRAY",
  PINK: "PINK",
} as const;
export type Color = (typeof Color)[keyof typeof Color];
export type Eagle = {
  id: number;
  name: string;
  ability: Generated<Ability>;
};
export type Elephant = {
  id: number;
  name: string;
  ability: Generated<Ability>;
  color: Color;
};
export type DB = {
  "birds.eagles": Eagle;
  "mammals.elephants": Elephant;
};