fs.writeFileSync in pdfDocument

var base64 = require('base64-stream');
var base64stream = pdfDoc.pipe(base64.encode());
pdfDoc.end();

var tempFileBase64 = ''

base64stream.on('data',function(buffer){
var part = buffer.toString();
    tempFileBase64 += part;
    console.log('process data ' + part);
});

base64streamEvaluations.on('end',function(){
  console.log('final output ' + tempFileBase64);
});