Heroku Postgres add-on connection string for Nodejs app - node.js

Question

I have a problem deploying a Nodejs app with a Postgresql database. The database comes from Heroku itself (Heroku Postgres add-on, hobby-dev). My app refused to connect to the database.
I found where the problem came from but I can't find a clean solution. And I think I could have misunderstood something (I'm new to Node and Heroku).
Heroku automatically gives me an environment variable DATABASE_CONFIG that includes the port:
postgres://username:password#hostname:port/databasename
Then, to connect with pg in my app, I use process.env.DATABASE_CONFIG as a connection string. I do something like:
const client = new Client({
connectionString: connectionString,
})
client.connect()
This fails to connect.
But if instead of using this environment variable, I cheat and change it, removing the port number from this connection string, it works.
I don't know why but the problem is that Heroku gives you this DATABASE_URL with the port included and you can't change it.
Did I do something wrong? Is there a clean solution to avoid that?
(because what I did is ugly as I hard-coded the DATABASE_CONFIG without the port directly in my code)
Thanks for your help!

Answer 1

First off, I would avoid using new Client() as this can lead to your connection being bottlenecked. Instead, use connection pooling. You can read a more indepth answer into why you want to do that here.
As for you direct issue, personally I have had trouble connecting to heroku postgres databases in the past, but here is a (basic) typical setup that works for me 99% of the time:
let pg = require('pg');
if (process.env.DATABASE_URL) {
pg.defaults.ssl = true;
}
// include an OR statement if you switch between a local dev db and
// a remote heroku environment
let connString = process.env.DATABASE_URL || 'postgresql://postgres:password#localhost:localpostgresport/yourlocaldbname';
const { Pool } = require('pg');
const pool = new Pool({
connectionString : connString
});
My first guess would be that it may have to do with ssl not being enabled. I know that has cause me problems in the past. Secondly, you want to make sure that you uses the process.env.DATABASE_URL, as environment variable should be set as the postgres connection string by Heroku.