Node POS

Library that offers easy API to communicate with point-of-sales printers, by serial way (usb), TCP/IP (wifi) and bluetooth.

Usage

import { AbstractAdapter, SerialAdapter, TcpAdapter, USBAdapter, listPrinters, Printer } from "@capvision/printer-pos";

const printers = await listPrinters();
const selectedPrinter = printers[0];

let adapter: AbstractAdapter;

if(selectedPrinter.type === "USB") {
    adapter = new USBAdapter({
        vendorId: selectedPrinter.vendorId,
        productId: selectedPrinter.productId,
    });
}
else if(selectedPrinter.type === "Network") {
    adapter = new TcpAdapter({
        host: selectedPrinter.host,
        port: selectedPrinter.port, // optional, defaults to 9100
    });
}
else {
    adapter = new SerialAdapter({
        path: selectedPrinter.path,
    });
}
// or directly adapter = new *Adapter(selectedPrinter);

const printer = new Printer(adapter);

await printer.open();

printer.setDefaultStyle({
    align: "left",
    bold: false,
    underline: false,
    double: false,
    font: "a",
});

await printer
    .text("=== Printing Test ===\n", { bold: true, underline: true })
    .text("Hello, this is a printing test.\n", { align: "center" })
    .text("We thank you for using our POS solution !\n\n", { font: "b" })
    .cut()
    .flush();

await printer.close();

Even easier :

import { AdapterFactory, listPrinters, Printer } from "@capvision/printer-pos";

const printers = await listPrinters();
const selectedPrinter = printers[0];
const adapter = AdapterFactory.create(selectedPrinter);
const printer = new Printer(adapter);

Network (TCP/IP) configuration

Ethernet / Wi-Fi printers are driven over a RAW ESC/POS socket — the de-facto standard "port 9100" transport (a.k.a. Epson RAW / JetDirect). Provide the host and, optionally, the port (default 9100):

const adapter = new TcpAdapter({ host: "192.168.1.50", port: 9100 });

AdapterFactory.create(printerInfo) builds a TcpAdapter when printerInfo.type === "Network", forwarding printerInfo.host and printerInfo.port. Network printers are not auto-discovered by listPrinters() (they require an IP/host known to the operator); the host app is expected to let the user enter the host/port and store it on PrinterInfo.

Status read-back (DLE EOT) is best-effort: many network printers do not answer, in which case Printer.getStatus() resolves to null.

Text size

Character magnification uses GS ! n (ESC/POS), supporting independent width/height multipliers from 1× to 8×:

printer.text("TITLE", { widthScale: 2, heightScale: 2 }); // double size
printer.text("HUGE",  { widthScale: 3, heightScale: 4 }); // 3× wide, 4× tall

The legacy boolean double flag still works (equivalent to 2×2) but explicit widthScale/heightScale take precedence when set. To map a logical point size (e.g. coming from a layout) onto the discrete POS paliers, use fontSizeToScale(fontSize, baseFontSize?) (baseline POS_BASE_FONT_SIZE = 10pt → 1×).

Serial configuration

Serial / Bluetooth printers default to 9600 8N1. Override (and persist) the link parameters per printer:

const adapter = new SerialAdapter({ path: "COM5", baudRate: 19200, parity: "even" });

AdapterFactory.create(printerInfo) forwards printerInfo.serial to the adapter, so storing a known-good configuration on PrinterInfo.serial avoids re-discovering it on every print.

Best-effort auto-detection (for printers that answer DLE EOT):

import { detectPrinterSerialConfig } from "@capvision/printer-pos";
const params = await detectPrinterSerialConfig("COM5"); // SerialParams | null

Text is encoded with the printer's code page (default cp1252, covering French accents and the € sign); change it via new Printer(adapter, { codePage: "cp858" }).

Notes

USB devices can work with Serial Port, or native USB.

Bluetooth devices almost always work Serial Port.