pdf-merger-js

In a Node.js environment, use the PDFMerger class to programmatically merge files. The library uses ESM (import) syntax.

Available Methods:

• add(pathOrFile, [pages]): Adds a PDF file or part of it. pages can be a single page number, an array of numbers, a comma-separated string, or a range string (e.g., '3-5' or '3 to 5').
• save(filename): Saves the merged PDF to the specified filename and resets the internal state.
• saveAsBuffer(): Exports the merged PDF as a Node.js Buffer.
• setMetadata(metadata): Sets metadata for producer, author, title, or creator.
• reset(): Resets the internal state to start a new document.

Example:

import PDFMerger from 'pdf-merger-js';

var merger = new PDFMerger();

(async () => {
  await merger.add('pdf1.pdf');  // merge all pages
  await merger.add('pdf2.pdf', 2); // merge only page 2
  await merger.add('pdf2.pdf', [1, 3]); // merge pages 1 and 3
  await merger.add('pdf2.pdf', '4, 7, 8'); // merge pages 4, 7 and 8
  await merger.add('pdf3.pdf', '3 to 5'); // merge pages 3 to 5
  await merger.add('pdf3.pdf', '3-5'); // merge pages 3 to 5

  await merger.setMetadata({
    producer: "pdf-merger-js based script",
    author: "John Doe",
    creator: "John Doe",
    title: "My live as John Doe"
  });

  await merger.save('merged.pdf');
})();

For browser-based applications (like React), import from the /browser entry point. This version is optimized for web environments and handles files as Blobs or File objects.

Available Methods:

• add(file): Adds a PDF File or Blob object.
• saveAsBlob(): Exports the merged PDF as a Blob.
• saveAsBuffer(): Exports the merged PDF as a Uint8Array.
• save(): Triggers a file download directly in the browser.
• setMetadata(metadata): Sets metadata for producer, author, title, or creator.
• reset(): Resets the internal state.

Example (React Component):

import PDFMerger from 'pdf-merger-js/browser';
import React, { useEffect, useState } from 'react';

const Merger = ({ files }) => {
  const [mergedPdfUrl, setMergedPdfUrl] = useState();

  useEffect(() => {
    const render = async () => {
      const merger = new PDFMerger();

      for(const file of files) {
        await merger.add(file);
      }

      await merger.setMetadata({
        producer: "pdf-merger-js based script"
      });

      const mergedPdf = await merger.saveAsBlob();
      const url = URL.createObjectURL(mergedPdf);

      setMergedPdfUrl(url);
    };

    render().catch((err) => {
      console.error(err);
    });
  }, [files]);

  return !mergedPdfUrl ? (
    <>{'Loading...'}</>
  ) : (
    <iframe
      height='1000'
      src={mergedPdfUrl}
      title='pdf-viewer'
      width='100%'
    ></iframe>
  );
};

The pdf-merge command allows you to merge multiple PDF documents or specific page ranges from them via the terminal. You can specify input files and use a # suffix to define page ranges.

Command Syntax: pdf-merge [options] <inputFiles...>

Options:

• -V, --version: Output the version number.
• -o, --output <outputFile>: Path for the merged PDF output file.
• -v, --verbose: Print verbose output.
• -s, --silent: Do not print any output to stdout (overwrites --verbose).
• -h, --help: Display help for the command.

Examples:

Merge pages 1-2 from the first input with pages 1, 2, and 5-7 from the second PDF:

pdf-merge --output ./merged.pdf ./input1.pdf#1-2 ./input2.pdf#1,2,5-7

Merge files from URLs (merging a local file with specific pages from a remote URL):

pdf-merge --verbose --output ./sample.pdf Testfile.pdf https://pdfobject.com/pdf/sample.pdf https://upload.wikimedia.org/wikipedia/commons/1/13/Example.pdf#2-3