print.java

public void printTickets(String ticketsArray, Promise promise) throws JSONException {
        JSONArray tickets = new JSONArray(ticketsArray);

        for (int i = 0; i < tickets.length(); i++) {
            JSONObject ticket = tickets.getJSONObject(i);
            String productName = ticket.getString("productName");
            String ticketUID = ticket.getString("ticketUID");

            try {
                commands.initialize();
                commands.fontSize(14);
                commands.alignCenter("Nome do Evento").lineFeed(1);
                commands.fontSize(18).alignCenter(productName).lineFeed(1);
                commands.fontSize(14);
                commands.qrCode(ticketUID).lineFeed(5).partialCut();
            }catch( IOException e) {
                promise.reject(COMMAND_ERROR, e);
            }
            catch (OutOfRangeException e) {
                promise.reject(OUT_OF_RANGE, e);
            }
        }

        try{
            //final cut
            commands.lineFeed(8);
            commands.fullCut();

            ByteArrayOutputStream generator = new ByteArrayOutputStream();
            generator.write(commands.getByteArray());

            printer.openPrinterConnection(getReactApplicationContext(), ThermalPrinterModule.this, ThermalPrinterModule.this);
            printer.print(generator.toByteArray());
            printer.closePrinter();

            promise.resolve("Impressão Concluída");
        }catch( IOException e) {
            promise.reject(PRINT_ERROR, e);
        }

    }