Select One and Only One or Throw

[JadenSWang]

Is there anything in drizzle-orm's toolkit which allows you to query and select for only one item and throw an error if multiple or zero results are returned? I'm in the middle of migrating from a strange mix of stored procedures and quite often do I find myself checking if result > 1 and not 0.

I imagine this could be done even quicker with the use of UNIQUE fields.

[0xPT]

Bump

[Angelelz]

Drizzle doesn't have this feature just yet but a workaround would look something like this:

// Define this helper somewhere in your codebase:
const takeUniqueOrThrow = <T extends any[]>(values: T): T[number] => {
  if (values.lenght !== 1) throw new Error("Found non unique or inexistent value")
  return values[0]!
}

// Use it in a query as follows:
const user = await db.select().from(users).where(eq(users.id, userId)).then(takeUniqueOrThrow);
//     ^? const user: { id: string; name: string; ... }

[vijayganeshpk]

Hello @Angelelz ,

Thank you for the sample code.

I am not too familiar with TypeScript so was wondering if the takeUniqueOrThrow thereby making it as below

export const takeUniqueOrThrow = <T>(values: T[]): T => {
  if (values.length !== 1)
    throw new Error("Found non unique or inexistent value");
  return values[0]!;
};

Am I missing some functionality based on this version of the function?

[Angelelz]

No, those are equivalent.

[capaj]

@Angelelz please include this or similar helper in drizzle

[Warchant]

You can also customize an error message

export const takeUniqueOrThrow = (message: string) => {
    return <T>(values: T[]): T => {
        if (values.length !== 1)
            throw new Error(`Found non unique or inexistent value: ${message}`);
        return values[0]!;
    };
}

[Tigatok]

@Angelelz not meaning to resurrect this thread, is the comment from Vijay technically better because the T extends any throws a linting error if expecting any?

Thanks in advance,