ColumnType incorrectly generated for pg lists

[ShadowAya]

issue

I use Kysely with a PostgreSQL database. In one of my tables. I have a key of type timestamp without time zone[].

The generated type:

export type Timestamp = ColumnType<Date, Date | string, Date | string>;

export interface RateLimiting {
  action_id: string;
  timestamps: Timestamp[];
  user_id: string;
}

this puts a list of Timestamps into timestamps, but from my knowledge, that is improper use of ColumnType.

what happens

When doing a query, the following happens:

const limit = await db.selectFrom('rate_limiting')
            .selectAll()
            .where('user_id', '=', ctx.user.id)
            .where('action_id', '=', action)
            .executeTakeFirst();
            
typeof limit?.timestamps[0]

this returns one of the Timestamps as is, so now we are working with a ColumnType instead of Date (the type in this example has __insert__, __select__ and __update__ properties)

possible solution

I created a utility type for this:

type List<T> = T extends ColumnType<infer S, infer I, infer U> ? ColumnType<S[], I[], U[]> : never;

export interface RateLimiting {
  action_id: string;
  timestamps: List<Timestamp>;
  user_id: string;
}

I hope this is helpful, and thanks for the work that's been done here to make the Kysely experience better. I would love to commit a fix straight to the repo, but I'm not very experienced with this kind of stuff, only TypeScript. It'd be appreciated if a more experienced maintainer looks into the actual generation of such types.

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