process.platform === 'Darwin'

[zimt28]

pdf-merge doesn't work on Mac, as the platform Darwin contains the string win. pdf-merge will ask for an absolute path for PDFtk.

[zimt28]

Making sure process.platform/ os.platform() isn't Darwin should be enough (here).

[wubzz]

Thanks for reporting this. I've opted to go by os.type() instead, since the issue you described would also occur on other platforms.