Cloud Run Functions + Cloud SQL + IAM Auth

I'm trying to connect my Cloud Run Function using IAM auth but it always errors saying that the password must be a string. How do I connect to my DB without the need of setting a password?

Code example:

  const connector = new Connector();
  const clientOpts = await connector.getOptions({
    instanceConnectionName: "project:us-central1:instance",
    ipType: IpAddressTypes.PRIVATE,
    authType: AuthTypes.IAM,
  })

  const pool = new Pool({
    ...clientOpts,
    user: 'sample-service-account@developer',
    database: 'my-db',
    max: 1,
  });

  const {rows} = await pool.query('SELECT NOW()');
  console.table(rows); 

  await pool.end();
  connector.close();

Error:

Unhandled error Error: SASL: SCRAM-SERVER-FIRST-MESSAGE: client password must be a string
    at /workspace/node_modules/pg-pool/index.js:45:11
    at process.processTicksAndRejections (node:internal/process/task_queues:95:5)
    at async /workspace/lib/exampleFunction.js:15:22
    at async /workspace/lib/lib/infrastructure/functions/functionWrapper.js:27:24
    at async /workspace/lib/lib/infrastructure/functions/onPublicCall.js:11:12
    at async /workspace/node_modules/firebase-functions/lib/common/providers/https.js:467:26

I figured it out. Apart from adding the roles to my IAM user, I also need to add the IAM user to my DB instance. Go to your instance -> Users -> Add User Account -> Cloud IAM. There, you add the full email of the service account your service is being deployed. Then you need to grant access of all tables/schemas to this user.