Receipt thermal printer in Electron

Question

I need to find a way of printing receipts in javascript from Electron. I already tried QZ-TRAY but it doesn't work because of Electron. I also tried node-thermal-printer but it also never worked for me. Does anybody here know how you can print receipts without asking the user in javascript (Electron)?

EDIT

Qz-tray offer a solution that is pretty good and hard to beat.

If you have the error RSVP is not defined you need to enable native javascript promises with this line.

qz.api.setPromiseType(resolver => new Promise(resolver));

Answer 1

Quoting the relevant comments...

"Well with QZ my problem was RSVP is not defined and with node-thermal-printer, the printer just never printed."

"for QZ it took all of 20secs to find this: https://qz.io/wiki/2.0-api-override"

Posting as asolution as the comments suggest it worked. Credits to @gilbert-gabriel for the help.

The RSVP promises are enabled by default, but native JS promises are supported via:

qz.api.setPromiseType(resolver => new Promise(resolver));

A more comprehensive example:

// Install dependencies:
/*
   npm install qz-tray js-sha256
*/

// Provide API overrides and start talking to QZ Tray:    
import * as qz from 'qz-tray';
import { sha256 } from 'js-sha256';

qz.api.setSha256Type(data => sha256(data));
qz.api.setPromiseType(resolver => new Promise(resolver));

qz.websocket.connect()
 .then(qz.printers.getDefault)
 .then(printer => console.log("The default printer is: " + printer))
 .then(qz.websocket.disconnect)
 .catch(err => console.error(err));