Missing outline when merging PDF files

[condorheroblog]

I use the following code to merge two PDFs, both of which have outlines. After merging, the newly generated PDF loses its outline. What should I do to ensure that the outline is preserved while merging PDFs.

const fs = require("node:fs");
const path = require("node:path");
const pdf = require("pdfjs");

const doc = new pdf.Document();
const pdf1 = fs.readFileSync(path.resolve(__dirname, "1.pdf"));
const pdf2 = fs.readFileSync(path.resolve(__dirname, "2.pdf"));

const ext1 = new pdf.ExternalDocument(pdf1);
const ext2 = new pdf.ExternalDocument(pdf2);

doc.addPagesOf(ext1);
doc.addPagesOf(ext2);

doc.asBuffer((err, data) => {
	if (err)
		console.error(err);

	else
		fs.writeFileSync("merge.pdf", data, { encoding: "binary" });
});

At present, I only know that the root outline can be obtained through the following code:

const fs = require("node:fs");
const Parser = require("./parser.js");

const parser = new Parser(fs.readFileSync("vitePress.pdf"));
parser.parse();
const getOutline = catalog.get("Outlines").object.properties;

Looking forward to your reply😉.

[rkusa]

Thanks for the report! This is probably similar to #130. I agree that it would be nice to have, but probably don't find the time to work on this myself anytime soon.