The proper way to use the node.js PostgreSQL module

In order to work with Postgres and node, Pg is the way to go. First, you need to install the pg module by running npm i pg. After that create a folder in your project and for now, let it name db. Inside that folder create an index.js file and add the given code to it.

const { Pool } = require('pg');
const pool = new Pool({
  connectionString: process.env.DATABASE_URL,//this is your connection string discussed in details below
  ssl: false,
  max: 20, // some sane value as per your project requirement
  idleTimeoutMillis: 30000,
  connectionTimeoutMillis: 2000,
});
module.exports = {
    query: (text, params) => pool.query(text, params)
  }

The connection string

PostgreSQL connection string is made in following format.

postgres://<username e.g postgres>:<password>@<db url eg localhost>:<port eg 5432>/<database name> an example connection string from one of my projects on local host is postgres://postgres:iwillnottell@127.0.0.1:5432/customer_query_vo

Using The Pool

Once you have created a index.js file inside db folder as discussed above you can easily import it and use it in your js files. An example import and use is given below

var db = require('../db');

// inside your async function
    const resultProperty = await db.query('select * from property where property_id=$1', [propertyId]);
// transaction examples 
await db.query('BEGIN') // begin transaction
//do your stuff
await db.query('COMMIT') //commit transaction
// if some thing fails then rollback
await db.query('ROLLBACK')

PG module is a very versatile and easy to use module though you might need pg-format If you want to insert multiple values or deal with collections.