var fontDescriptors = {}; // required font setup, see ...
var docDefinition = {}; // this is what you see in all the docs
var Printer = require('pdfmake');
var printer = new Printer(fontDescriptors);

// get a reference to the PdfKit instance, which is a streaming interface
var pdfDoc = printer.createPdfKitDocument(docDefinition);

// pipe to a file or response object
function streamTo(pdfDoc) {
  // writeStream can be an fs object, response object, etc
  var writeStream = fs.createWriteStream('pdfs/output.pdf');
  var pdfDoc = printer.createPdfKitDocument(docDefinition);
  pdfDoc.pipe(writeStream); // streaming interface
}

// turn the stream into a Buffer
// Usage: getDoc(pdfDoc, function (err, buffer, pages) { var base64 = buffer.toString('base64'); /* app logic */ });
function getDoc(pdfDoc, cb) {
  // buffer the output
  var chunks = [];
  
  pdfDoc.on('data', function(chunk) {
  	chunks.push(chunk);
  });
  pdfDoc.on('end', function() {
  	var result = Buffer.concat(chunks);
  	cb(null, result, pdfDoc._pdfMakePages);
  });
  pdfDoc.on('error', cb);
  
  // close the stream
  pdfDoc.end();
}