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!

Use pg-promise-demo as reference, because it works fine there. — vitaly-t
– vitaly-t, Commented Dec 26, 2018 at 4:43
Thanks! I was actually looking at that as well, and I was wondering how I could initialize the database without the "IExtensions" interface (or is it required for this to work)? The reason I ask is because the "IExtension", from what I understand, just extends the "UsersRepository" and "ProductsRepository" extensions, which I won't need in my smaller program (as of right now). Is there a way to create the initialization options without the IExtension interface? Thanks! — Ryan Arifin
– Ryan Arifin, Commented Dec 26, 2018 at 17:57
Nevermind, I figured out the problem. Apparently in Javascript ES6, you need to use "import pgPromise from 'pg-promise'" instead of "import * as pgPromise from 'pg-promise';". — Ryan Arifin
– Ryan Arifin, Commented Dec 26, 2018 at 20:42

vitaly-t · Accepted Answer · 2019-07-13 16:40:29Z

5

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.

answered Jul 13, 2019 at 16:40

vitaly-t

26.1k17 gold badges129 silver badges151 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

Having Trouble Initializing Postgresql Database Through PG-Promise

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related