Merge Two or More PDFs

The code above enables you to combine multiple PDF documents created from different HTML contents into a single PDF file.

Two HTML contents have been rendered into separate PDF documents. The PdfDocument.mergePdf method is utilized to merge the two PDF documents, pdfdoc_a and pdfdoc_b, into a single PDF document named "merged."

The merging process is not limited to freshly rendered PDFs; it can also be applied to existing PDF documents using this method.

import { PdfDocument } from "@ironsoftware/ironpdf";

(async () => {
  // Open or render the first PDF document
  // Either from HTML, file path, or URL — here assuming file paths:
  const pdfA = await PdfDocument.open("path/to/pdfdoc_a.pdf");
  const pdfB = await PdfDocument.open("path/to/pdfdoc_b.pdf");

  // Merge multiple PdfDocument instances into one
  const merged = await PdfDocument.mergePdf([pdfA, pdfB]);

  // Save the merged PDF to a new file
  await merged.saveAs("merged.pdf");
})();

import { PdfDocument } from "@ironsoftware/ironpdf";

(async () => {
  // Open or render the first PDF document
  // Either from HTML, file path, or URL — here assuming file paths:
  const pdfA = await PdfDocument.open("path/to/pdfdoc_a.pdf");
  const pdfB = await PdfDocument.open("path/to/pdfdoc_b.pdf");

  // Merge multiple PdfDocument instances into one
  const merged = await PdfDocument.mergePdf([pdfA, pdfB]);

  // Save the merged PDF to a new file
  await merged.saveAs("merged.pdf");
})();

Explanation

• Import: uses PdfDocument from the @ironsoftware/ironpdf package
• Opening PDFs: PdfDocument.open(...) loads existing PDF files (rather than rendering HTML) — appropriate when merging pre‑existing PDFs.
• Merging PDFs: PdfDocument.mergePdf([pdfA, pdfB]) combines the two documents into a single instance
• Saving the result: merged.saveAs("merged.pdf") writes out the merged PDF, equivalent to Python’s merger.write(...)

This code is useful for combining PDFs generated from different sources or pre-existing files, facilitating easy document management.