How to add custom metadata in PDF files using ReactJS?

To add custom metadata in a PDF file using ReactJS, you can use a library like pdf-lib, which allows you to manipulate PDF documents in the browser. Here's an example code snippet that shows how to add custom metadata to a PDF file using pdf-lib:

import { PDFDocument } from 'pdf-lib';

// Load the existing PDF file
const existingPdfBytes = ...; // load the PDF file as a byte array
const pdfDoc = await PDFDocument.load(existingPdfBytes);

// Add custom metadata
pdfDoc.setTitle('My PDF Document');
pdfDoc.setAuthor('John Doe');
pdfDoc.setSubject('A PDF Document');
pdfDoc.setKeywords(['pdf', 'react', 'metadata']);

// Serialize the modified PDF
const pdfBytes = await pdfDoc.save();

// Save the modified PDF to a file or send it to the server
...

In this example, PDFDocument class is used to load the existing PDF file and modify its metadata. You can set the title, author, subject, and keywords of the PDF document using the setTitle(), setAuthor(), setSubject(), and setKeywords() methods, respectively. Finally, you can save the modified PDF using the save() method and then save the file or send it to the server as needed.