Error: [Error: ORA-12560: TNS:protocol adapter error] { errorNum: 12560, offset: 0 }

Ok, you got this error using nodejs and oracledb :

Error:  [Error: ORA-12560: TNS:protocol adapter error] {
      errorNum: 12560,
      offset: 0
    }

Solution:

Because your username, password, connection string are all undefined.

connection = await OracleDB.getConnection({
user: undefined,
password: undefined,
connectString: undefined,
});

If you are using dotenv , it means you are getting undefined