Use sql parameter string typing instead of explicit generics in Typescript

[geekuillaume]

Is your feature request related to a problem? Please describe.

This is a potential improvement to remove the need to explicitly specify the generic <ISelectUserIdsQuery> when using the sql method. It's inspired by GraphQL codegenerator.

Describe the solution you'd like

During the codegen operation, in addition of generating the IOperationQuery, IOperationResult and IOperationParams, we can add an overload of the sql method that specify the exact string passed as parameter.

For example, when declaring the queries in typescript:

import { sql } from '@pgtyped/runtime';

const selectUser = sql(`SELECT * from users`);

it would generate a new file (called "queries.types.ts" for example):

import { sql as sourceSql } from '@pgtyped/runtime';

export type ISelectUserParams = void;
export interface ISelectUserQueryResult {
  id: string;
}
export interface ISelectUserQuery {
  params: ISelectUserParams;
  result: ISelectUserQueryResult;
}

export function sql(s: 'SELECT * FROM users;'): ReturnType<typeof sourceSql<ISelectUserQuery>>;
export function sql(s: string): unknown {
  return sourceSql([s] as any);
}

Then, in the original file, the import can be changed to import {sql} from './queries.types.ts' and then selectUser will be typed without any other change. This also links the query string to the typing, if the query is changed, the typing reverts to unknown which can then trigger other errors. This will prevent mistakes linked to changing the query but not regenerating the codegen.

Notes

This would require changing the calling method from using a template string to a normal string parameter:

sql`SELECT * from users;`

to

sql(`SELECT * from users;`)

This is necessary until this typescript issue is fixed: microsoft/TypeScript#33304

[adelsz]

Great suggestion @geekuillaume. That would be a significant DX boost.
I will try to work on this as part of the next release. Let me know if you would like to take a stab at it first.

[reverofevil]

When/if that TS issue is resolved, please, ping me. As might be obvious from the message there, I have a simple prototype for type-checked SQL literals.

[JesseVelden]

Great suggestion @geekuillaume. That would be a significant DX boost. I will try to work on this as part of the next release. Let me know if you would like to take a stab at it first.

I've gave it a stab in #520 😉

[scottsidwell]

@adelsz anything we can do to help get this ticket / change some more attention? even if it's releasing #520 behind a beta / experimental flag? Happy to help however we can

[water-a]

@adelsz looks like #520 was merged in, wondering when we could get a release so I can start using it in my project!

[adelsz]

This has now been released as part of v2.3.0.
Many thanks to @JesseVelden for his PR 🙂