Creates multiple drizzle clients without creating new connections each time

create-drizzle-clients.ts

import {
  drizzle as drizzleClient,
  PostgresJsDatabase,
} from "drizzle-orm/postgres-js";
import postgres from "postgres";
import * as database1Schema from "./schemas/database1/schema";
import * as database2Schema from "./schemas/database2/schema";

const createDrizzleClientSingleton = <TSchema extends Record<string, unknown>>(
  db: string,
  schema: TSchema
): PostgresJsDatabase<TSchema> => {
  let connectionString = null;

  if (db === "app1") {
    connectionString = process.env.APP_1_DATABASE_URL!;
  } else {
    connectionString = process.env.APP_2_DATABASE_URL!;
  }

  const client = postgres(connectionString);

  return drizzleClient(client, { schema });
};

// The types here ensure you get correct type completions
declare const globalThis: {
  app1DrizzleGlobal: PostgresJsDatabase<typeof database1Schema>;
  app2DrizzleGlobal: PostgresJsDatabase<typeof database2Schema>;
} & typeof global;

const app1Drizzle =
  globalThis.app1DrizzleGlobal ??
  createDrizzleClientSingleton("app1", app1Schema);
const app2Drizzle =
  globalThis.app2DrizzleGlobal ??
  createDrizzleClientSingleton("app2", app2Schema);

export { crawlerDrizzle, appDrizzle };

if (process.env.NODE_ENV !== "production") {
  globalThis.app1DrizzleGlobal = app1Drizzle;
  globalThis.app2DrizzleGlobal = app2Drizzle;
}