[v3] .describe() doesn't work as expected

[mohe2015]

import { sql } from "./database.js";

const query = sql`SELECT * FROM users WHERE id = ${1}`

console.log(await query.describe())
console.log(await query.execute())

await sql.end()

Hi,

I expected this to show the describe and then the results but it shows the describe twice. Is this intended behaviour and is there a way to do what I want?

[mohe2015]

In particular I would love this to be as efficient as possible as I want to use this to add dynamic typescript to it. I don't know how the describe works internally or if that information is there anyways so it would have no overhead.

[porsager]

The query instance is not meant to be reused / reissued, but I can see why that would be expected, so it'd be interesting to think about .execute() and friends as a way to reuse queries.

[mohe2015]

The query instance is not meant to be reused / reissued, but I can see why that would be expected, so it'd be interesting to think about .execute() and friends as a way to reuse queries.

I think for now this is fine. I hope to manage to implement this without this (which is probably also better because it doesn't involve breaking changes for now). Thanks for helping though.

[porsager]

Yeah, I'm not sure it's a breaking change as much as uncharted territory, but that's also why I moved it to discussions since I'm not sure if it's a good idea or if it would see much usage yet.

[mohe2015]

import { deepStrictEqual } from "assert";
import { sql } from "./database.js";

const description = {
  types: [ 23, 16 ],
  columns: {
    id: 23,
    username: 1043,
    openid_id: 1043,
    password_hash: 1043,
    type: 17425,
    project_leader_id: 23,
    group: 1043,
    age: 23,
    away: 16,
    password_changed: 16,
    force_in_project_id: 23,
    computed_in_project_id: 23,
    deleted: 16,
    last_updated_by: 23
  }
} as const;

export function typedSql<Q extends readonly number[], R extends { [column: string]: number }>(description: { types: Q; columns: R }) {
  return async (template: TemplateStringsArray, ...args: DescriptionTypes<Q>) => {
    const { types: computed_query_types, columns: computed_column_types_1 } = await sql(template, ...args).describe()

    const computed_column_types = Object.fromEntries(computed_column_types_1.map(v => [v.name, v.type]))

    const computed_description = {
      types: computed_query_types,
      columns: computed_column_types
    }

    deepStrictEqual(computed_description, description)

    return await sql<DescriptionTypes<R>[]>(template, ...args).execute()
  }
}

type DescriptionTypes<T> = {
   -readonly [K in keyof T]: T[K] extends 23 ? number : T[K] extends 1043 ? string : T[K] extends 16 ? boolean : string;
}

const results = await typedSql(description)`SELECT * FROM users WHERE id = ${1} AND away = ${false}`

console.log(results)

console.log(results[0].type)

await sql.end();

Initial design. Hopefully not completely broken. If it holds up to it's promises I think it's awesome.

[porsager]

I'm not into typescript, so can't say, but did you see #192 ?