"Do not know how to serialize a BigInt" when inserting numbers

[gskril]

I have the example SQL schema from Cloudflare's docs:

CREATE TABLE IF NOT EXISTS Customers (CustomerId INTEGER PRIMARY KEY, CompanyName TEXT, ContactName TEXT);

INSERT INTO Customers (CustomerID, CompanyName, ContactName) VALUES (1, 'Alfreds Futterkiste', 'Maria Anders'), (4, 'Around the Horn', 'Thomas Hardy'), (11, 'Bs Beverages', 'Victoria Ashworth'), (13, 'Bs Beverages', 'Random Name');

And this Kysely code (removed some Worker boiler plate code for simplicity):

import { Kysely } from 'kysely';
import { D1Dialect } from 'kysely-d1';
import { Env } from '../env';

interface Customers {
  CustomerID: number;
  CompanyName: string;
  ContactName: string;
}

interface Database {
  Customers: Customers;
}

const db = new Kysely<Database>({ dialect: new D1Dialect({ database: env.DB }) });

await db
  .insertInto('Customers')
  .values({
    CustomerID: 7,
    ContactName: 'test',
    CompanyName: 'test',
}).execute();

When the Worker runs, it successfully creates a row in the table but throws the following error:

Do not know how to serialize a BigInt

[aidenwallis]

Hmm, not sure how to properly handle this case, thanks for raising. I'll look into it in a little bit. I have a feeling this is more of a Kysely level thing.

[kbuffington]

I ran into the exact same issue with Kysely and this seemed to be the only question with someone else experiencing exactly what I was (inserts working, but the same error message returning back from the API call), so I thought I'd include my fix. I'm guessing that some of the boilerplate @gskril left off is actually the cause of the problem. I was doing something like this:

const unqueriedEntities = await db
    .insertInto('unqueried_entities')
    .values(entityArray)
    .execute();
return NextResponse.json({ message: 'Unqueried Entity saved successfully', unqueriedEntities });

Assuming that what I'd be given back was the rows I'd just entered because the return type was InsertResult[]. Instead what I was getting back was:
{ insertId: undefined, numInsertedOrUpdatedRows: 2n }
which my NextResponse.json call was attempting to serialize, and it didn't know what do to with the "2n" BIGINT. Because this was happening on the backend it was really confusing at first.

The simple fix was just to tell it what we want returned using the returning method, like so:

const unqueriedEntities = await db
    .insertInto('unqueried_entities')
    .values(entityArray)
    .returning('id')
    .execute();

No more issues serializing and I get back a nice: { id: 19 } when I insert.