pg.singleton.ts

import { Pool } from 'pg'
import * as dotenv from 'dotenv'
import { colors } from 'colors'
dotenv.config()

export class DatabasePool {
  constructor() {
    if (!!DatabasePool.instance) {
      return DatabasePool.instance;
    }

    DatabasePool.instance = this
    console.log('Instantiating DatabasePool =)'.bgGreen.black)
    this.pool = new Pool({
      user: process.env.DB_USER,
      host: process.env.DB_HOST,
      database: process.env.DB_DBNAME,
      password: process.env.DB_PASS,
      port: parseInt(process.env.DB_PORT)
    })
    return this
  }

  getPool() {
    return this.pool
  }
}

// usage
	const db = new DatabasePool() // get singleton
	db.getPool().query('SELECT * FROM users').then(data => { console.log(data.rows) })