Adding custom types - how to specify a dynamic OID?

[ohueter]

I'm trying to add a custom type for the vector type added by the pgvector extension. The following code works on my machine:

postgres(process.env.POSTGRES_URL, {
  types: {
    vector: {
      to: 16390,
      from: [16390],
      serialize: (embedding: number[]) => JSON.stringify(embedding),
      parse: (value: string) => JSON.parse(value),
    },
  },
})

However, it doesn't work anywhere else as OIDs seem to be dynamic / not stable between Postgres instances.

I tried querying for the OID of the DB instance via

sql`SELECT oid FROM pg_type WHERE typname = 'vector'`

which obviously works, but I couldn't find a way to add the custom type after the sql client was instantiated. Opening, querying, closing using one sql client and then instantiating a second client with the correct OID seems excessive.

Whats the recommended way to do this?

[ohueter]

I solved this for now by querying the pg_type table using a disposable client before instantiating the client I use throughout the app. However, if my understanding of this package is correct, the pg_type table is read on client creation anyway. Maybe the types option could (additionally) accept a callback function as well, passing the read types as parameter?