[FEATURE]: Select with tRPC

Describe what you want

The idea comes from GraphQL. One of GraphQL’s advantages is that it allows the client to specify exactly which fields and relations they need in a query.

Using Drizzle with tRPC can essentially achieve the same functionality, but it's not standardized. Normally, we would define the inputs in tRPC procedures and try to map these inputs to Drizzle’s select configuration.

However, why not pass the Drizzle select configuration directly as the input and feed it into Drizzle? This approach would be very useful as it provides GraphQL-like capabilities, making it more performant and efficient for both users and developers.

Here’s an example of what I mean:

export const article = publicProcedure
  .input(
    z.object({
      findConfig: z.custom<Magic>((_) => true),
    }),
  )
  .query(({ ctx, input }) => ctx.db.query.Article.findFirst(input.findConfig));

function App() {
  const { data } = api.article.useQuery({
    findConfig: {
      columns: {
        id: true,
        title: true,
      },
      with: {
        comments: true,
      },
    },
  });
  data?.id;
  data?.createdAt; // TS error: Property 'createdAt' does not exist on type
  data?.comments;
}

Of course, we need to restrict the input values to ensure only columns and relations configs can be used. Otherwise, it would be like passing raw SQL, which can do anything.

Currently, tRPC doesn't support generic output based on input, but we can still annotate the output type like this:

I’m able to achieve this, but the generic typing becomes very complex. It's something like this:

import type * as schema from "@acme/db/schema";

type TSchema = ExtractTablesWithRelations<typeof schema>;
type TFields = TSchema["Article"];
type TSelection = Omit<DBQueryConfig<"many", true, TSchema, TFields>, "limit">;
type ArticleFindConfig = KnownKeysOnly<
  TSelection,
  Omit<DBQueryConfig<"many", true, TSchema, TFields>, "limit">
>;

export const article = publicProcedure
  .input(
    z.object({
      findConfig: z.custom<ArticleFindConfig>((_) => true),
    }),
  )
  .query(({ ctx, input }) => ctx.db.query.Article.findFirst(input.findConfig));

function useArticleQuery<
  TSchema extends ExtractTablesWithRelations<typeof schema>,
  TFields extends TSchema["Article"],
  TSelection extends Omit<
    DBQueryConfig<"many", true, TSchema, TFields>,
    "limit"
  >,
>(input: {
  findConfig?: KnownKeysOnly<
    TSelection,
    Omit<DBQueryConfig<"many", true, TSchema, TFields>, "limit">
  >;
}) {
  return api.article.useQuery<
    BuildQueryResult<TSchema, TFields, TSelection>,
    BuildQueryResult<TSchema, TFields, TSelection>
  >(input);
}

function App() {
  const { data } = useArticleQuery({
    findConfig: {
      columns: {
        id: true,
        title: true,
      },
      with: {
        comments: true,
      },
    },
  });
  data?.id;
  data?.comments;
}

My question is how can I get the select config directly from db.query.Article.findFirst and also infer the query result so I don't need to copy the generic type by myself?

drizzle-team / drizzle-orm

[FEATURE]: Select with tRPC #2593

Describe what you want