Drizzle Team•11mo ago

Typing a helper function parameter to be a table with required column(s)

I'm having a hard time typing some helper functions where I need some params to accept any table as long as it implements certain required columns (key and type). Here's what i'm aiming for:

export function withTranslation<T extends AnyTable, TT extends AnyTable</* How to type this to enforce certain columns, e.g. "locale"? */>>(
  event: RequestEvent | ServerLoadEvent,
  table: T,
  translationsTable: TT,
  join: { field: ValueOf<T['_']['columns']>; reference: ValueOf<TT['_']['columns']> }
) {
  return dbpool.$with('tt').as((db) =>
    db
      .select({
        ...getTableColumns(table),
        ...getTableColumns(translationsTable),
      })
      .from(table)
      .leftJoin(
        translationsTable,
        and(
          eq(translationsTable.locale, event.locals.locale),
                            // ^^^^^^Property "locale" does not exist on type TT
          eq(join.field, join.reference))
        )
    );
}

export function withTranslation<T extends AnyTable, TT extends AnyTable</* How to type this to enforce certain columns, e.g. "locale"? */>>(
  event: RequestEvent | ServerLoadEvent,
  table: T,
  translationsTable: TT,
  join: { field: ValueOf<T['_']['columns']>; reference: ValueOf<TT['_']['columns']> }
) {
  return dbpool.$with('tt').as((db) =>
    db
      .select({
        ...getTableColumns(table),
        ...getTableColumns(translationsTable),
      })
      .from(table)
      .leftJoin(
        translationsTable,
        and(
          eq(translationsTable.locale, event.locals.locale),
                            // ^^^^^^Property "locale" does not exist on type TT
          eq(join.field, join.reference))
        )
    );
}

Anyone have experience with this?

7 Replies

Angelelz•11mo ago

How about:

TT extends AnyTable & { locale: any }

TT extends AnyTable & { locale: any }

iolyd•11mo ago

Hmmm, that could very well do! For some reason I was trying to use AnyTable 's generic instead of just doing an intersection

Angelelz•11mo ago

I mean, you could, but why complicate it:

TT extends AnyTable<{ name: "", columns: {locale: any}, dialect: "your dialect" }>

TT extends AnyTable<{ name: "", columns: {locale: any}, dialect: "your dialect" }>

iolyd•11mo ago

And say I want to be stricter regarding locale's type since I know it should be implemented on tables using a common definition:

/* Could implement more columns... */
export const baseColumns = {
  locale: locale('locale')
    .references(() => locales.locale, {
      onDelete: 'cascade',
      onUpdate: 'cascade',
    })
    .notNull(),
  //...
};

/* Could implement more columns... */
export const baseColumns = {
  locale: locale('locale')
    .references(() => locales.locale, {
      onDelete: 'cascade',
      onUpdate: 'cascade',
    })
    .notNull(),
  //...
};

I'm struggling to infer a table-agnostic column type for this.

TT extends AnyTable & { [K in keyof typeof baseColumns]: AnyColumn & (typeof baseColumns)[K]> }

TT extends AnyTable & { [K in keyof typeof baseColumns]: AnyColumn & (typeof baseColumns)[K]> }

(sorry for the deluge of things named locale)

Angelelz•11mo ago

The columns that you pass to a table definition get transformed by the table function What you could do is use one of the tables where those columns are implemented and pull the types from them:

type BaseColumns = Pick<typeof MyTable, "locale" | "anotherColumn" | "anotherOne">

type BaseColumns = Pick<typeof MyTable, "locale" | "anotherColumn" | "anotherOne">

iolyd•11mo ago

Alrighty, here's what I've got then:

export function withTranslation<
  T extends AnyTable,
  TT extends AnyTable & { [K in keyof TranslationBaseColumns]: AnyColumn },
  J extends { field: ValueOf<T['_']['columns']>; reference: ValueOf<TT['_']['columns']> },
>(
  event: RequestEvent | ServerLoadEvent,
  table: T,
  translationsTable: TT,
  join: J | ((table: T, translationsTable: TT) => J)
) {
  const { field, reference } = 'field' in join ? join : join(table, translationsTable);
  return dbpool
    .select({
      ...getTableColumns(table),
      ...getTableColumns(translationsTable),
    })
    .from(table)
    .leftJoin(
      translationsTable,
      and(eq(translationsTable.locale, event.locals.locale), eq(field, reference))
    );
}

export function withTranslation<
  T extends AnyTable,
  TT extends AnyTable & { [K in keyof TranslationBaseColumns]: AnyColumn },
  J extends { field: ValueOf<T['_']['columns']>; reference: ValueOf<TT['_']['columns']> },
>(
  event: RequestEvent | ServerLoadEvent,
  table: T,
  translationsTable: TT,
  join: J | ((table: T, translationsTable: TT) => J)
) {
  const { field, reference } = 'field' in join ? join : join(table, translationsTable);
  return dbpool
    .select({
      ...getTableColumns(table),
      ...getTableColumns(translationsTable),
    })
    .from(table)
    .leftJoin(
      translationsTable,
      and(eq(translationsTable.locale, event.locals.locale), eq(field, reference))
    );
}

Ah, yeah I could try that

Angelelz•11mo ago

Then you could do:

TT extends AnyTable & BaseColumns

TT extends AnyTable & BaseColumns

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Typing a helper function parameter to be a table with required column(s)