JavaScript anchor file download - override file name from Content-Disposition header

Question

As mentioned in the title, I'm using JS, an anchor URL, and a download attribute to get a file from an external system.

The problem is that I have to download it under a specific filename and the PDF file preview contains a Contain-Disposition header with the filename from the server. For Chrome, the title from that header has higher priority and I don't know how to customize the title or override that header title.

Is there any workaroud for this using only client-side JavaScript?

Answer 1

As suggested by @Dai in the comments, you can use an implementation similar to the following to override the file name in the Content-Disposition header:

fetch("url_to_your_pdf_file.pdf")
  .then((response) => response.blob())
  .then((blob) => {
    const url = URL.createObjectURL(blob);
    const a = document.createElement('a');
    a.href = url;
    a.download = "desired_filename.pdf";
    a.click();
    URL.revokeObjectURL(url);
  })
  .catch((error) => {
    console.error("Error fetching the PDF:", error);
  });

The fetch function is part of pure JavaScript, you do not require any external libraries to use it.