Print ZPL, TSPL and EZPL labels from Node.js

Label printers each speak their own language: Zebra uses ZPL, TSC and most low-cost units use TSPL, Godex uses EZPL. retail-print-kit lets you describe the label once and encode it for any of them.

Build a label

Positions are in dots from the top-left corner. At 203 dpi there are 8 dots per millimetre; b.mm(10) converts.

const { LabelBuilder, encodeZpl, encodeTspl, encodeEzpl, labelToSvg } = require('retail-print-kit');

const b = new LabelBuilder({ widthMm: 50.8, heightMm: 25.4, dpi: 203 }); // 2 x 1 inch
b.text(18, 14, 'Coffee Beans 1lb', 26)
 .text(92, 65, '$12.99', 85, { bold: true })
 .barcode(35, 140, '036000291452', 'UPC_A', 35)
 .qr(330, 20, 'https://example.com/i/1', { module: 3 })
 .box(2, 2, 402, 199, 2);

const zpl = encodeZpl(b.label);    // string, starts with ^XA
const tspl = encodeTspl(b.label);  // bytes, starts with SIZE
const ezpl = encodeEzpl(b.label);  // string, starts with ^Q
const svg = labelToSvg(b.label);   // preview

Elements: text, barcode (CODE128, EAN13, EAN8, UPC_A, UPC_E, CODE39, ITF, CODABAR), qr, box, rect and image. Text, barcodes and QR codes take rotation: 0 | 90 | 180 | 270.

Send it to the printer

Label printers on the network listen on port 9100, like receipt printers.

const { encodeLabel } = require('retail-print-kit');
const { NetTransport } = require('retail-print-kit/net');

const t = new NetTransport('192.168.1.60');
await t.open();
await t.write(Buffer.from(encodeLabel(b.label, 'zpl'))); // 'zpl' | 'tspl' | 'ezpl'
await t.close();

Use b.copies(3) for several labels.

Labels from a template

A label can be a JSON layout with data placeholders, which is what the designer exports:

const { renderLabel } = require('retail-print-kit');

const template = {
  name: 'shelf-label', version: 1, kind: 'label', widthMm: 50.8, heightMm: 25.4, dpi: 203,
  elements: [
    { type: 'text', x: 18, y: 14, value: '{{name}}', height: 26 },
    { type: 'text', x: 92, y: 65, value: '{{price | money:$}}', height: 85, bold: true },
    { type: 'barcode', x: 35, y: 140, value: '{{upc}}', format: 'UPC_A', height: 35 },
    { type: 'text', x: 18, y: 70, value: 'SALE', height: 24, invert: true, when: 'sale' },
  ],
};
const label = renderLabel(template, { name: 'Coffee Beans 1lb', price: 12.99, upc: '036000291452', sale: true });

From the command line

npx retail-print-kit print --template shelf.json --data item.json --language zpl --net 192.168.1.60
npx retail-print-kit print --template shelf.json --data item.json --out label.svg
npx retail-print-kit verify-label --language tspl --net 192.168.1.60

Which language does my printer use?

Related: the template designer.

Install

npm install retail-print-kit

All guides · Designer · npm · GitHub