nodejs - officegen - pipesCount

Question

为了创建word文档，我使用officegen包：

  var fs = require('fs');
  var officegen = require('officegen');

  var docx = officegen ({
    'type': 'docx',
    'title': 'test title'
  })

  var pObj = docx.createP ();
  pObj.addText('Text');
  pObj.addText('with color', {color: '000088'});
  pObj.addText('and back color.', {color: '00ffff',back: '000088'});

  var out = fs.createWriteStream(__dirname + '/tmp/out.docx');
  docx.generate(out)
  out.on('error', function(err) {
    console.log('out error: ' + err);
  });

  docx.on('finalize', function(written) {
    console.log('Finish to create a Word file.\nTotal bytes created: ' + written + '\n');
  });

  docx.on('error', function(err) {
    console.log('docx appeared: ' + err);
  });

会发生什么：

File get created, with content 'PK'

为什么？

控制台中抛出错误：

Cannot read property 'pipesCount' of undefined

之前有人遇到过这个问题吗？

问候和感谢