escpos-ts API - v1.0.0
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    Class Dummy

    In-memory ESC/POS printer for testing and validation.

    All bytes written via _raw() are appended to an internal buffer. Retrieve the accumulated output with the output getter or clear it with clear.

    open() and close() are no-ops — the class is always "connected".

    import { Dummy } from 'escpos-ts';

    const printer = new Dummy('TM-T88V');
    printer.setWithDefault({ bold: true, align: 'center' });
    printer.textln('Hello');
    printer.cut();

    const bytes = printer.output;
    // bytes is a Buffer containing the complete ESC/POS byte stream

    1.0.0

    Hierarchy (View Summary)

    Index

    Constructors

    constructor

    Properties

    magic profile

    Accessors

    output

    Methods

    _raw barcode blockText cashdraw clear close cut hw image linedisplay linedisplayClear linedisplaySelect lineSpacing ln open printAndFeed qr set setWithDefault softwareColumns text textln checkBarcode

    Constructors

    Properties

    magic: MagicEncode
    profile: PrinterProfile

    Accessors

    Methods

    _raw

    • Print a hardware barcode.

      Sends the appropriate GS k sequence for the requested barcode type and function type. Supports all types defined in BARCODE_TYPES (UPC-A, UPC-E, EAN8, EAN13, CODE39, ITF, NW7/CODABAR, CODE93, CODE128, and GS1 variants for Function Type B).

      Parameters

      • code: string

        Barcode data string.

      • bc: string

        Barcode type name (e.g. 'CODE128', 'EAN13'). Names are normalised (non-alphanumeric removed, uppercased) before lookup.

      • opts: BarcodeOptions = {}

        Optional barcode appearance settings; see BarcodeOptions.

      Returns void

      BarcodeTypeError if the type is unrecognised or unsupported.

      BarcodeCodeError if code fails format validation and opts.check is true (default).

      BarcodeSizeError if height or width are out of range.

      printer.barcode('012345678905', 'EAN13', { pos: 'BELOW', height: 80 });
      printer.barcode('{B12345678', 'CODE128', { functionType: 'B' });

      1.0.0

    • Print a word-wrapped text block.

      Wraps txt at word boundaries to fit within the column width of the selected font, as reported by the active printer profile.

      Parameters

      • txt: string

        UTF-8 string to wrap and print.

      • font: FontName = 'a'

        Font to use for column-width lookup ('a' or 'b'; default: 'a').

      • Optionalcolumns: number

        Override column count (uses profile value if omitted).

      Returns void

      1.0.0

    • Cut the paper.

      Feeds 6 lines before cutting unless feed is false. Falls back to a full cut when the profile does not support partial cuts, and vice versa.

      Parameters

      • mode: "FULL" | "PART" = 'FULL'

        'FULL' (default) for a complete cut, 'PART' to leave a small uncut section.

      • feed: boolean = true

        Feed paper before cutting (default: true).

      Returns void

      Error if mode is not 'FULL' or 'PART'.

      1.0.0

    • Send a hardware control command to the printer.

      Action Command Effect
      'INIT' ESC @ Clear print buffer and reset modes to defaults
      'SELECT' ESC = Select printer as the active peripheral
      'RESET' ESC ? Soft reset

      Parameters

      • action: "INIT" | "SELECT" | "RESET"

        One of 'INIT', 'SELECT', or 'RESET'.

      Returns void

      Error if action is not one of the three valid values.

      1.0.0

    • Print an image from a file path or raw image Buffer.

      Supported formats: PNG, JPEG, BMP, GIF, TIFF.

      The image is:

      1. Loaded and decoded (alpha channel composited onto white background).
      2. Converted to greyscale and thresholded at luminance 128.
      3. Optionally centred within the profile's media width.
      4. Split into vertical fragments if taller than fragmentHeight.
      5. Encoded using the selected impl and written via _raw().

      impl options:

      • 'bitImageRaster' (default) — GS v 0; widest printer compatibility.
      • 'graphics' — GS ( L; better alignment on some models.
      • 'bitImageColumn' — ESC *; required for printers like IT80-002.

      Parameters

      • source: string | Buffer<ArrayBufferLike>

        Absolute file path or raw image Buffer.

      • opts: ImageOptions = {}

        Image rendering options; see ImageOptions.

      Returns Promise<void>

      ImageWidthError if the image is wider than the profile's declared media width.

      await printer.image('./receipt-logo.png', { center: true });
      await printer.image('./receipt-logo.png', { impl: 'bitImageColumn' });

      1.0.0

    • Set or reset the line spacing.

      When called without arguments, resets line spacing to the printer default (ESC 2). When spacing is provided, sets the line spacing to spacing / divisor inches per dot using the matching ESC/POS command:

      Divisor Command Range
      60 ESC A 0–85
      180 ESC 3 0–255
      360 ESC + 0–255

      Parameters

      • Optionalspacing: number

        Spacing value in dots (omit to reset).

      • divisor: 60 | 180 | 360 = 180

        Unit divisor: 60, 180, or 360 (default: 180).

      Returns void

      RangeError if divisor is not one of 60 | 180 | 360.

      RangeError if spacing is outside the valid range for the divisor.

      1.0.0

    • Print a QR code.

      Two rendering modes are available, controlled by opts.native:

      • Software mode (native: false, default) — generates the QR matrix locally using the qrcode package and sends it as a raster image via image. Works on all printers that support raster images.

      • Native mode (native: true) — sends the five GS ( k sub-commands (set model, size, error correction, store data, print) directly. Requires the printer to have a built-in QR engine (most Epson TM series).

      Parameters

      • content: string

        The string to encode (UTF-8).

      • opts: QrOptions = {}

        QR code appearance options; see QrOptions.

      Returns Promise<void>

      Error if ec, size, or model values are outside valid ranges.

      await printer.qr('https://example.com', { size: 4, ec: QR_ECLEVEL_M });

      1.0.0

    • Apply text styles with full defaults merged in.

      Merges opts over a complete default set (left align, Font A, no bold, no underline, 1×1 size, density 9) before calling set. Also auto-enables customSize when width or height > 1 is requested without an explicit size mode, so callers do not need to set the flag manually.

      Calling with no arguments resets the printer to standard text defaults.

      Parameters

      • opts: TextStyleOptions = {}

        Partial style overrides (default: {} — full reset).

      Returns void

      printer.setWithDefault({ bold: true, align: 'center', height: 2 });
      printer.textln('TOTAL');
      printer.setWithDefault(); // reset all styles

      1.0.0

    • Print a row of text in software-defined columns.

      Lays out textList into adjacent fixed-width columns, word-wrapping each cell and aligning content per the corresponding align entry. Outputs one textln() call per row of the resulting grid.

      Parameters

      • textList: string[]

        Array of strings, one per column.

      • widths: number | number[]

        Total line width (split evenly) or per-column width array.

      • align: Alignment | Alignment[]

        Alignment for all columns or per-column alignment array.

      Returns void

      // Receipt item line: name left-aligned, price right-aligned
      printer.softwareColumns(['Americano', '$3.50'], [30, 10], ['left', 'right']);

      1.0.0

    text

    • text(txt: string): void

      Print a string using automatic encoding selection.

      Characters are encoded via MagicEncode, which automatically selects the best code page for each segment of the string and emits the necessary ESC t n code-page-switch commands.

      Parameters

      • txt: string

        UTF-8 string to print.

      Returns void

      1.0.0

    • Validate a barcode code string against the format rules for a given barcode type.

      Checks that the code length falls within an allowed range and that the string matches the required character set for the barcode type.

      Parameters

      • bc: string

        Barcode type name (e.g. 'CODE128', 'EAN13').

      • code: string

        Barcode data string to validate.

      Returns boolean

      true if the code is valid for the given type.

      1.0.0

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