Download all the files via javascript

download.js

// download files via predicate function. Simply paste this into the developer console on a site to download files. It will download all of them at once!
function downloadAllFiles(predicate) {

  var files = Array.prototype.slice.call(document.getElementsByTagName("a"), 0).filter((tag) => predicate(tag.href)).map((t) => t.href)

  files.forEach((p) => {
    var clickEvent = document.createEvent("MouseEvent")
    clickEvent.initMouseEvent("click", true, true, window, 0, 0, 0, 0, 0, false, false, false, false, 0, null)
    var downloadButton = document.createElement("a")
    downloadButton.href = p
    downloadButton.download = p.slice(-p.lastIndexOf('/'))
    downloadButton.dispatchEvent(clickEvent);
  })
}

// change the predicate here to specify which files you want to download.
downloadAllFiles((link) => link.slice(-4) === '.pdf')