Bulk remove pages fails after 8 pages

[jackwshepherd]

In my app, there is a functionality that allows people to "split" a long PDF into two PDFs.

The way it currently works is as follows:

• User scrolls through the PDF, and selects the split point. Everything from that point and before will be extracted into a new PDF
• Load the PDF, and create an array of every page that needs removing from the source. (e.g. if we make the split point Page 5, the array will be [0 , 1, 2, 3, 4].

This is the code:

// Initiate PDFDocument object
      let pdf = await PDFDocument.create();

      // Now load into a PDFDocument object
      const file = await readFileAsync(filename);

      const source = await PDFDocument.load(file);

       // Make an array of all pages to extract
      let newPages = [];
      for (i = 0; i < splitPoint; i++) {
        newPages.push(i);
      }

      // Copy those pages to a new PDF
      const copiedPages = await pdf.copyPages(source, newPages);
      copiedPages.forEach(page => pdf.addPage(page));
      const newEntry = await pdf.save();

      // Now remove pages from the source document and save back
      newPages.forEach(page => {
        source.removePage(0);
      });
      const newSource = await source.save();

Whenever the newPages array is greater than 8, I always get this error - regardless of the PDF. By this point I have already error checked to see that the "split point" is actually within the document, i.e. that there are in fact at least 9 pages in the document. So this error is not being produced by trying to remove a page when the document doesn't have that page contained within it.

Error: Index out of bounds: 0/-1 (b)
[0]     at PDFPageTree.removeLeafNode (/Users/me/workspace/app/server/node_modules/pdf-lib/cjs/core/structures/PDFPageTree.js:105:19)
[0]     at PDFPageTree.removeLeafNode (/Users/me/workspace/app/server/node_modules/pdf-lib/cjs/core/structures/PDFPageTree.js:109:20)
[0]     at PDFCatalog.removeLeafNode (/Users/me/workspace/app/server/node_modules/pdf-lib/cjs/core/structures/PDFCatalog.js:27:22)
[0]     at PDFDocument.removePage (/Users/me/workspace/app/server/node_modules/pdf-lib/cjs/api/PDFDocument.js:338:22)
[0]     at /Users/me/workspace/app/server/routes/pdfRoutes.js:73:16
[0]     at Array.forEach (<anonymous>)
[0]     at /Users/me/workspace/app/server/routes/pdfRoutes.js:72:16

Any ideas? Is there a better way to do this?

[Hopding]

Hello @jackwshepherd!

What version of pdf-lib are you using?

[jackwshepherd]

1.4.1. I just upgraded to 1.5.0 and still get that error

[Hopding]

Can you please share a document I can use to reproduce the issue?

[jackwshepherd]

Just emailed it to you - thanks a lot. Hopefully we can understand why, and post the response here. Just didn't want the doc to be public.

[jackwshepherd]

It seems to work fine with PDFs that are text - seems to arise only with PDFs that are comprised of images. Very odd.

[Hopding]

@jackwshepherd I found and fixed the bug that was causing this issue in #441.

[Hopding]

Version 1.5.1-rc2 is now published. It contains the fix for this issue.

You can install this new version with npm:

npm install pdf-lib@1.5.1-rc2

It's also available on unpkg:

• https://unpkg.com/pdf-lib@1.5.1-rc2/dist/pdf-lib.js
• https://unpkg.com/pdf-lib@1.5.1-rc2/dist/pdf-lib.min.js

As well as jsDelivr:

• https://cdn.jsdelivr.net/npm/pdf-lib@1.5.1-rc2/dist/pdf-lib.js
• https://cdn.jsdelivr.net/npm/pdf-lib@1.5.1-rc2/dist/pdf-lib.min.js

[Hopding]

Version 1.6.0 is now published. It contains the fix for this issue. The full release notes are available here.

You can install this new version with npm:

npm install pdf-lib@1.6.0

It's also available on unpkg:

• https://unpkg.com/pdf-lib@1.6.0/dist/pdf-lib.js
• https://unpkg.com/pdf-lib@1.6.0/dist/pdf-lib.min.js

As well as jsDelivr:

• https://cdn.jsdelivr.net/npm/pdf-lib@1.6.0/dist/pdf-lib.js
• https://cdn.jsdelivr.net/npm/pdf-lib@1.6.0/dist/pdf-lib.min.js