Node.js package

@thermal-label/labelwriter-node provides USB and TCP transport implementations and a high-level LabelWriterPrinter class for use in Node.js.

Install

npm install @thermal-label/labelwriter-node

USB

The USB transport wraps the usb npm package (libusb). It claims interface 0 and uses bulk endpoints for data transfer.

import { openPrinter } from '@thermal-label/labelwriter-node';

const printer = await openPrinter();
// or target a specific device by serial number:
const printer2 = await openPrinter({ serialNumber: 'AB1234' });

Linux udev

See Getting started — Linux udev rule for the required udev configuration.

TCP

Wireless LabelWriter models expose port 9100 over the network.

import { openPrinterTcp } from '@thermal-label/labelwriter-node';

const printer = await openPrinterTcp('192.168.1.100');
// custom port:
const printer2 = await openPrinterTcp('192.168.1.100', 9200);

Listing printers

import { listPrinters } from '@thermal-label/labelwriter-node';

const printers = listPrinters();
for (const p of printers) {
  console.log(p.device.name, p.path, p.serialNumber);
}

Printing text

await printer.printText('Hello, world!', {
  density: 'high',
  copies: 2,
  invert: false,
  scaleX: 1.5,
});

Printing images

Requires the optional dependency @napi-rs/canvas:

npm install @napi-rs/canvas

await printer.printImage('./label.png', {
  threshold: 128,
  dither: false,
  rotate: 90,
  density: 'normal',
});

Checking status

const status = await printer.getStatus();
console.log(status.ready);    // true if printer is ready to print
console.log(status.paperOut); // true if paper out
console.log(status.errors);   // string[] of active errors

Error recovery

If the printer is stuck after an error, send the recovery sequence:

await printer.recover();
const status = await printer.getStatus();

API

listPrinters()

Returns PrinterInfo[] for all connected Dymo LabelWriter USB printers.

openPrinter(options?)

Opens the first matching USB printer. Options:

Option	Type	Description
vid	number	Filter by USB vendor ID
pid	number	Filter by USB product ID
serialNumber	string	Filter by serial number

openPrinterTcp(host, port?)

Connects to a printer over TCP. Default port is 9100.

LabelWriterPrinter

Method	Returns	Description
getStatus()	Promise<PrinterStatus>	Read printer status
print(bitmap, options?)	Promise<void>	Send pre-encoded bitmap
printText(text, options?)	Promise<void>	Render and print text
printImage(path, options?)	Promise<void>	Load and print image file
recover()	Promise<void>	Send error recovery sequence
close()	Promise<void>	Close transport connection