Can merging PDFs be made faster and simpler?

[ysageev]

Hi! First, let me tell you how grateful I am for pdf-lib. I'm finding it full featured and reliable. Thank you for making this available as FOSS.

My one issue is that merging PDFs is slow, at least the way I'm doing it. When I send out reports, I have to append a bunch of related supporting PDFs, using this code:

const mergePDF = async (pdfbuf, pdfdest) => {
   let pdfDoc = await PDFDocument.load(pdfbuf, { ignoreEncryption: true, returnCopy: true })
   let copiedPages = await pdfdest.copyPages(pdfDoc, pdfDoc.getPageIndices())
   copiedPages.forEach((page) => {
      pdfdest.addPage(page)
   })
   return pdfdest
}

Right now, we need to call addPage() for every page in copiedPages. Why couldn't the API have something addPages(copiedPages)?

Better yet, because merging an entire PDF is so common, why can't there be an API addition like pdfdst.merge(pdfsrc) which is highly optimized?

[StillOnMyWay]

This is exactly what I came here to ask Andrew - @Hopding . I figured 💯 % that this was an intentional decision not to add this feature, because you've already created embedPages and copyPages, so I was wondering why no addPages

[acestronautical]

The slow speed of PDF merging is a bottleneck for us over at https://github.com/momijizukamori/bookbinder-js

It's especially frustrating that this can't be done with promises.