node-thermal-printer

When using a system printer (via printer:auto or printer:Name), you must provide a driver. You can use the printer or electron-printer modules depending on your environment.

Using Electron or Node.js drivers:

const ThermalPrinter = require("node-thermal-printer").printer;
const PrinterTypes = require("node-thermal-printer").types;
const electron = typeof process !== 'undefined' && process.versions && !!process.versions.electron;

let printer = new ThermalPrinter({
  type: PrinterTypes.EPSON,
  interface: 'printer:My Printer',
  driver: require(electron ? 'electron-printer' : 'printer')
});

Using a custom driver: You can pass a custom driver object during initialization or via setPrinterDriver():

let printer = new ThermalPrinter({
  type: PrinterTypes.EPSON,
  interface: 'printer:My Printer',
  driver: MyCustomDriver
});

// Or after initialization:
printer.setPrinterDriver(MyCustomDriver);

The ThermalPrinter instance provides a variety of methods to build a print job. Commands are appended to an internal buffer and executed when .execute() is called.

Execution & Connection:

• await printer.isPrinterConnected(): Returns boolean status.
• await printer.execute(): Executes all queued commands. Returns success or throws error.
• await printer.raw(Buffer): Prints raw data immediately.

Text & Formatting:

• printer.print(text) / printer.println(text): Append text (with or without newline).
• printer.bold(bool): Set text bold.
• printer.underline(bool) / printer.underlineThick(bool): Set underline thickness.
• printer.alignCenter() / printer.alignLeft() / printer.alignRight(): Text alignment.
• printer.setTextSize(height, width): Set text size (0-7).
• printer.setTypeFontA() / printer.setTypeFontB(): Set font type.

Layout & Lines:

• printer.drawLine(): Draws a line.
• printer.newLine(): Inserts a break line.
• printer.leftRight(leftText, rightText): Prints text on left and right sides.
• printer.table(array): Prints a table with equal columns.
• printer.tableCustom(array): Prints a table with custom settings (text, align, width, cols, bold).

Hardware Actions:

• printer.openCashDrawer(): Kicks the cash drawer.
• printer.cut() / printer.partialCut(): Cuts the paper.
• printer.beep(): Sounds the internal buzzer.
• printer.upsideDown(bool): Rotates content 180 degrees.

To use the printer, instantiate the ThermalPrinter class with a configuration object.

Key Configuration Options:

• type: Use PrinterTypes.STAR or PrinterTypes.EPSON.
• width: Number of characters in one line.
• interface: The connection method (e.g., tcp://xxx.xxx.xxx.xxx).
• characterSet: Use CharacterSet constants (e.g., CharacterSet.PC852_LATIN2).
• removeSpecialCharacters: Boolean (default: false).
• lineCharacter: Character used for lines (default: -).
• breakLine: Use BreakLine constants (WORD, CHARACTERS, or NONE).
• options: An object containing timeout (ms) for network connections (default: 3000).

const { ThermalPrinter, PrinterTypes, CharacterSet, BreakLine } = require('node-thermal-printer');

const printer = new ThermalPrinter({
  type: PrinterTypes.STAR,
  width: 48,
  interface: 'tcp://xxx.xxx.xxx.xxx',
  characterSet: CharacterSet.PC852_LATIN2,
  removeSpecialCharacters: false,
  lineCharacter: '=',
  breakLine: BreakLine.WORD,
  options: {
    timeout: 5000
  }
});

The library supports various 1D and 2D barcode types with customizable settings.

Code128 Barcode:

• width: "SMALL", "MEDIUM", or "LARGE".
• height: 50 to 80.
• text: 1 (No text), 2 (Bottom), 3 (No text inline), 4 (Bottom inline).

QR Code:

• cellSize: 1 to 8.
• correction: "L", "M", "Q", or "H".
• model: 1, 2 (standard), or 3 (Micro QR).

PDF417:

• rowHeight: 2 to 8.
• width: 2 to 8.
• correction: 1 to 40.
• truncated: boolean.
• columns: 1 to 30, or 0 for auto.

MaxiCode:

• mode: 2 (US), 3 (International), 4 (Unformatted Standard Error), 5 (Unformatted Enhanced Error), 6 (Hardware devices).

printer.code128("Code128", {
    width: "LARGE",
    height: 80,
    text: 2
});

printer.printQR("QR Code", {
    cellSize: 3,
    correction: 'M',
    model: 2
});

printer.pdf417("PDF417", {
    rowHeight: 3,
    width: 3,
    correction: 1,
    truncated: false,
    columns: 0
});

printer.maxiCode("MaxiCode", {
    mode: 4
});

For STAR printers, the settings object can include characters and mode keys.

Settings: characters

Settings: mode