Having Trouble Initializing Postgresql Database Through PG-Promise

Question

I'm completely new to Express/Postgresql and I'm trying to learn them to create a web application. After some poking around, I decided that I wanted to develop my back-end with TypeScript. I successfully converted all my other files from JavaScript to TypeScript, but I still can't figure out how to initialize the pg-promise connection in TypeScript!

I've been trying to follow the TypeScript guidelines in this link here. https://github.com/vitaly-t/pg-promise/tree/master/typescript

// Initialize the PostGres database conneciton for use throughout 
the entire application
import {IMain, IDatabase} from 'pg-promise';
import * as pgPromise from 'pg-promise';

const pgp: IMain = pgPromise({
    query(e: any) {
        console.log('QUERY RESULT:', e.query);
    },
    receive(data: any, result: any, e: any) {
        console.log(`DATA FROM QUERY ${e.query} WAS RECEIVED.`);
    }
});

const connection: any = {
    host: 'localhost',
    port: 5432,
    database: 'RushHub',
    user: 'RyanArifin',
    password: null
}
const db: IDatabase<any> = pgp(connection);
export {
    db
};

I currently am getting the error "TS2349: Cannot invoke an expression whose type lacks a call signature. Type 'typeof pgPromise' has no compatible call signatures." This error is coming from when I try to set my initialization options. Any help would be appreciated, thanks!

Answer 1

This is standard TypeScript configuration flag - esModuleInterop. When set to true, the import syntax is import pgPromise from 'pg-promise';, and when false, which is the default, the syntax is import * as pgPromise from 'pg-promise';.

The library gives you example for the default TypeScript configuration.