This is my implementation of ESCPOS Printing from within node nw.js applications  
ADVANTAGE: nothing else needed i.e. no dependencies except built in modules:  
'fs' , 'os' ( in fact only needed when using on multiple platforms), and 'child process'

CEAVEAT: as its based on copying files to the printer-queue biderectional commands are not supported  
Tried to implement all basically necessary (and common betweeen printer models ) commands in an easy usable fashion
 
TODO: improve error tracking, implement more of the full command list, implement OSX

Prerequisites:  
On Win powershell is now used instead of cmd(net view) to detect printers  
At least one RAW-printer needs to be installed on the system :  
Under WINDOWS : just use the printer driver to install, most modern printers support both modes (driver and RAW) automatically
and !!! share the printer using a NAME which will be listed when network shares are ealuated  
On LINUX (and OSX): just install a (driverless) RAW Printer it will be listed by lp

Usage:
 ```javascript
 Printer = require('escpos_printing.js');
 Printer.ESCPOS_INIT();
 Printer.append(put commands and functions here);
 var sucess = Printer.ESCPOS_PRINT(currentPrinter);
    if(!sucess){
       alert(Printer.ESCPOS_LASTERROR);
    }           

```
Functions summary:  
ESCPOS_INIT : Initialize globals and lists printers to array  
append : adds commands and Text to the "Print Buffer"  
ESCPOS_CMD : submit a command (as defined in the set)  
ESCPOS_PRINT : collect "Printer Buffer" write it to a prt file and send the file to the printer-queue  
ESCPOS_IMAGEFILE : print image from a file  
ESCPOS_BARCODE : Print Barcodes  
ESCPOS_QRCODE : Print QR-Codes  
ESCPOS_CPBYNUMBER : Select a codepage ( Named Versions available as extra command sets)  
ESCPOS_CP_EPSON : Select codepage as defined by epson  
ESCPOS_CP_STAR : Select Codepage as defined by STAR using standard ESCPOS Command  
STAR_CP : Select codepage using a special command used by star printers  
ESCPOS_CHARSET : select international characterset

for more examples of usage look at demo.js