How to modify the first pageNumber or execute JS in header or footer template with Chrome DevTools Protocol's printToPDF?

 The Chrome DevTools Protocol is a set of tools and methods that allow you to programmatically control Chrome and communicate with it. It provides a low-level interface to the browser's internals, including its debugging and testing tools. One of the methods provided by the Chrome DevTools Protocol is printToPDF, which allows you to generate a PDF of the current page.

However, the printToPDF method does not provide a way to directly modify the page number or execute JavaScript in the header or footer of the generated PDF. If you want to modify the page number or add custom JavaScript to the header or footer of a PDF generated using printToPDF, you will need to use a PDF library or tool that provides this functionality.

One option is to use a library like PDFKit, which is a popular JavaScript library for generating and manipulating PDFs. With PDFKit, you can use the text method to add text to the header or footer of a PDF, and you can use the pageNumber method to add the current page number.

Here is an example of how you might use PDFKit to add a page number and some custom text to the header and footer of a PDF:

const PDFDocument = require('pdfkit');
const doc = new PDFDocument();

// Add a page number to the header and footer
doc.text('Page ' + doc.page.number, {
  align: 'right',
  margin: [0, 0, 10, 0],
});

// Add some custom text to the header and footer
doc.text('My Custom Header/Footer Text', {
  align: 'center',
  margin: [0, 10, 0, 0],
});

Keep in mind that this is just an example, and you will need to adjust the code to suit your specific needs. Additionally, there are many other PDF libraries and tools that you can use to modify the header and footer of a PDF, so you may want to explore your options and choose the one that best fits your needs.

To use a PDF library or tool with the printToPDF method, you will need to generate the PDF using printToPDF, and then use the library or tool to modify the PDF. For example, you could generate the PDF using printToPDF, save it to a file, and then use the PDF library or tool to open the file, modify it, and save it back to a new file.

In summary, the Chrome DevTools Protocol's printToPDF method provides a way to generate a PDF of the current page, but it does not provide a way to directly modify the page number or execute JavaScript in the header or footer of the generated PDF. To do this, you will need to use a PDF library or tool that provides this functionality.