printPDFFileInBuffer.js

// Windows does not support PDF formats, but you can use imagemagick-native to achieve conversion from PDF to EMF.

var printer = require("../lib"),
    fs = require('fs'),
    path = require('path'),
    filename = process.argv[2],
    printername = process.argv[3];

if(process.platform == 'win32') {
    throw 'Not yet supported for win32'
}

if(!filename || filename == '-h') {
    throw 'PDF file name is missing. Please use the following params: <filename> [printername]'
}

filename = path.resolve(process.cwd(), filename);
console.log('printing file name ' + filename);

fs.readFile(filename, function(err, data){
  if(err) {
    console.error('err:' + err);
    return;
  }
  console.log('data type is: '+typeof(data) + ', is buffer: ' + Buffer.isBuffer(data));
    printer.printDirect({
        data: data,
        type: 'PDF',
        success: function(id) {
            console.log('printed with id ' + id);
        },
        error: function(err) {
            console.error('error on printing: ' + err);
        }
    })
});