Inspired by Supabase way of querying database, using a simple JavaScript method chaining.

database-query.js

// node-postgres
const { Pool } = require('pg')

// Connection String
const config = {
  connectionString: (process.env.NODE_ENV === 'production') ? process.env.DATABASE_URL : 'postgres://me:password@localhost:5432/database_name'
}

/*
====================================
Query helper
====================================
How to use:

const query = new Query()

const resultA = await query.select().from('countries').where({ currency: 'USD' }).go()

const resultB = await query.select('id, name, email').from('users').go()

const resultC = await query
  .select()
  .from('posts')
  .where(
    {
      published: true,
      author: 'glauber'
    }
  )
  .go()

====================================

The output result will be the database query result, 
which can be an Array of objects or a simple Object.

I wish I could remove the go() at the end, but right now
not sure how to do it. I hope you like it and feel free
to contribute.
====================================
*/

export class Query {
  constructor() {
    this.text = ''
    this.values = []
  }

  select(q) {
    this.text = q == undefined ? 'SELECT *' : `SELECT ${q}`
    return this
  }

  from(q) {
    if (q === undefined) throw new Error('~FROM está vazio.')
    this.text += ` FROM ${q}`
    return this
  }

  where(q) {
    const { length } = Object.keys(q)
    let sentence = ''
    this.values = []

    Object.entries(q).forEach(([k, v], i) => {
      const index = (i + 1)
      const match = `${k} = $${index}`

      this.values.push(v)
      sentence += `${match}`

      if (length > 1 && index < length) {
        sentence += ', '
      }
    })

    this.text += ` WHERE ${sentence}`
    return this
  }

  orderBy(q) {
    if (q === undefined) throw new Error('~ORDER BY está vazio.')
    this.text += ` ORDER BY ${q}`
    return this
  }

  async go() {
    return new Promise(async (resolve, reject) => {
      const pool = new Pool(config)

      try {

        const { rows } = await pool.query(this.text, this.values)

        if (rows.length === 1) {
          resolve(rows[0])
        } else {
          resolve(rows)
        }

        pool.end()

      }
      catch (e) { reject(e) }

    })
  }
}