net.Stream is not a constructor - Node Postgres

I'm trying to connect a Node.js app with a PostgreSQL server. It seems that no matter what I use, I end up with the same error:

bundle.js:16177 ERROR: TypeError: net.Stream is not a constructor
at new Connection (bundle.js:10133)
at new Client (bundle.js:9704)
at Object.create (bundle.js:11308)
at Pool._createResource (bundle.js:510)
at Pool.dispense [as _dispense] (bundle.js:498)
at Pool.acquire (bundle.js:573)
at Pool.pool.connect (bundle.js:11359)
at PG.connect (bundle.js:10876)
at bundle.js:1642

At first I was declaring a new pg.Client() like the example in the documentation here, but got the above error discovered that might be a bad idea according to this stack overflow post.

I tried using pg.connect():

var pg = require('pg'); //postgresql dependency
var connectionString = "postgres://postgres:thisissuchagoodpassword@PostgreSQL/localhost:5432/Milestone1DB"

console.log("Initiating...");
//var connectionString = "postgres://postgres:[email protected]/localhost:5432/Milestone1DB";
//var client = new pg.Client();

//connect to the database
console.log("Attempting to connect to the database");
pg.connect(function (err, client, done)
{
  if(err)
  {
    console.log("Error connecting to the database.");
     throw err;
  }

  client.query("SELECT DISTINCT state FROM business ORDER BY state", function (err, result)
  {
   if(err)
    {
      console.log("Query resulted in an error.");
      throw err;
    }

    console.log(result.rows[0]);

    client.end(function (err)
    {
      if(err)
      {
        console.log("Error disconnecting from the databse.");
        throw err;
      }
    });
  });
});

Here is the pg-promise code that I tried:

var pgp = require('pg-promise');

var cn = {
    host: 'localhost', // server name or IP address;
    port: 5432,
    database: 'Milestone1DB',
    user: 'postgres',
    password: 'thisissuchagoodpassword'
};

var db = pgp(cn); // database instance;

db.any("select distict state from business order by state;")
    .then(data => {
        console.log("DATA:", data);
    })
    .catch(error => {
        console.log("ERROR:", error);
    });

I must be missing something, but I don't know where to look. Thank you to anyone who can help me figure out what this error means.