Merging PDFs in Node

Question

Hi i'm trying to merge pdf's of total of n but I cannot get it to work.

I'm using the Buffer module to concat the pdf's but it does only apply the last pdf in to the final pdf.

Is this even possible thing to do in node?

var pdf1 = fs.readFileSync('./test1.pdf');
var pdf2 = fs.readFileSync('./test2.pdf');

fs.writeFile("./final_pdf.pdf", Buffer.concat([pdf1, pdf2]), function(err) {
    if(err) {
        return console.log(err);
    }

    console.log("The file was saved!");
});

There are currently some libs out there but they do all depend on either other software or programming languages.

score 19 · Accepted Answer · answered Dec 12 '16 at 13:12

What do you expect to get when you do Buffer.concat([pdf1, pdf2])? Just by concatenating two PDFs files you won’t get one containing all pages. PDF is a complex format (basically one for vector graphics). If you just added two JPEG files you wouldn’t expect to get a big image containing both pictures, would you?

You’ll need to use an external library. https://github.com/wubzz/pdf-merge might work for instance.

score 8 · Answer 2 · answered Apr 27 '18 at 13:36

8

HummusJS is another PDF manipulation library, but without a dependency on PDFtk. See this answer for an example of combining PDFs in Buffers.

answered Apr 27 '18 at 13:36

Zach Esposito

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1

This is important for those people using services like Firebase that don't allow the installation of PDFtk – Gabriel Garrett Oct 21 '18 at 03:20
Is it possible to merge 7 Pdfs? – Daud khan Apr 15 '19 at 11:58
5

HummusJS is now unsupported. Prebuilt binaries are already missing and I couldnt get it to run on first try – phil294 Apr 21 '20 at 19:43

score 0 · Answer 3 · answered May 07 '21 at 14:34

Aspose.PDF Cloud SDK for Node.js can merge/combine pdf documents without depending on any third-party API/Tool. However, currently, it works with cloud storage(Aspose Internal Storage, Amazon S3, DropBox, Google Drive Storage, Google Cloud Storage, Windows Azure Storage, FTP Storage). In near future, we will provide support to merge files from the request body(stream).


const { PdfApi } = require("asposepdfcloud");
const { MergeDocuments }= require("asposepdfcloud/src/models/mergeDocuments");
var fs = require('fs');

pdfApi = new PdfApi("xxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxx", "xxxxxxxxxxxxxxxxxxxxx");

const file1 = "dummy.pdf";
const file2 = "02_pages.pdf";
const localTestDataFolder = "C:\\Temp";

const names = [file1, file2];
const resultName = "MergingResult.pdf";
const mergeDocuments = new MergeDocuments();
mergeDocuments.list = []; 
names.forEach( (file) => {
        mergeDocuments.list.push(file);
    });


// Upload File
pdfApi.uploadFile(file1, fs.readFileSync(localTestDataFolder + "\\" + file1)).then((result) => {  
                     console.log("Uploaded File");    
                    }).catch(function(err) {
    // Deal with an error
    console.log(err);
});

// Upload File
pdfApi.uploadFile(file2, fs.readFileSync(localTestDataFolder + "\\" + file2)).then((result) => {  
                     console.log("Uploaded File");    
                    }).catch(function(err) {
    // Deal with an error
    console.log(err);
});


// Merge PDF documents
pdfApi.putMergeDocuments(resultName, mergeDocuments, null, null).then((result) => {    
    console.log(result.body.code);    
}).catch(function(err) {
    // Deal with an error
    console.log(err);
});

//Download file
const outputPath = "C:/Temp/" + resultName;

pdfApi.downloadFile(outputPath).then((result) => {    
    fs.writeFileSync(localPath, result.body);
    console.log("File Downloaded");    
}).catch(function(err) {
    // Deal with an error
    console.log(err);
});

Merging PDFs in Node

3 Answers3

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