Originally forked from here

ESC/POS XML

Cross platform JavaScript library that implements the thermal printer ESC / POS protocol and provides an XML interface for preparing templates for printing.

Features

• Text
• Text line
• Feed line
• Bold text
• Underline text
• Font size
• Small mode
• White mode
• Align
• Barcode
• QRcode
• Paper cut node
• Image (base64) (png only)
• XML with mustache

Tested manually on following environments or platforms

• React Native (Android)
• React Native (iOS)
• React Native Web
• Server side (NodeJs)
• Desktop applications (nwjs & electron)
• Other node environment (terminal)

Installation

  yarn add @tillpos/xml-escpos-helper

Examples

With an XML template + plain object input (regular text).

import { EscPos } from '@tillpos/xml-escpos-helper';

// store this template somewhere `s3` or as `static asset` based on your preference 
const template = `
  <?xml version="1.0" encoding="UTF-8"?>
  <document>
    <align mode="center">
      <bold>
        <text-line size="1:0">{{title}}</text-line>
      </bold>
    </align>

    {{#thankyouNote}}
    <align mode="center">
      <text-line size="0:0">  {{{thankyouNote}}}</text-line>
    </align>

    <line-feed />

    <paper-cut />
  </document>
`;

const input = {
  title: 'Sample',
  thankyouNote: 'Welcome...!'
};

const buffer = EscPos.getBufferFromTemplate(template, input);
// send this buffer to a stream (eg.: bluetooth or wifi)

With an XML template + png image (base64)

  const template =  `<?xml version="1.0" encoding="UTF-8"?>
  <document>
    <align mode="center">
      <bold>
        <text-line size="1:0">{{title}}</text-line>
      </bold>
        
      <image density="d24">
        {{base64PngImage}}
      </image>
    </align>    
  </document>`;

  const input = {
    title: 'PNG - base64',
    base64PngImage: `data:image/png;base64,iVBORw0KGgoAAA+P/AaNn2GPEMgEFAAAAAElFTkSuQmCC`
  };

  const buffer = EscPos.getBufferFromTemplate(template, input);

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TODO

• Font styles (font family)
• Image bitmap conversion improvements
• jpeg support
• Add example apps to repo
• Removed uglify for some reason, need to bring it back
• Improve image rendering

Common issues

• If there is any delay you observe while printing with this library it is mostly due to image manipulations (try without image 😷 )

Useful links / resources

• ESC / POS Commands manual
• A blog post explaiing about printing images with ESCPOS
• Similar library for serverside - node-escpos.

Limitations on the react-native framework

• FileReader.readAsArrayBuffer was not implemented.
• Most of popular image manupulation libraries does not have support for react-native. eg : jimp, jpeg-js and sharp. We can use these libraries with some native node lib implemented in react native (some sort of polyfill).
• For png this library seems to be faster, but when tested this library with it, it is not retaining pixels at some places)
• Use this node-libs-react-native if we need to use this library in react native (adds some mock or js implementation for fs, stream etc)

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Contributions of any kind welcome! ❤️