How to use @taggedTemplate generate js with tagged template literals

what do you mean by object functions?

In the meanwhile, the easiest solution by far is just to initialize your sql function in raw js and bind to it:

%%raw(`import Postgres from "postgres"
let sql = Postgres("postgres://xxx:xxxx@localhost:5432/xxxxxx")`)
@taggedTemplate
external sql: (array<string>, array<'sqlParam>) => promise<'data> = "sql"

let foo = sql`hello`

Playground link