Base64 to pdf error: cannot download

Summary:

Hi experts

Content (required):

I am trying to download files from external database

and they are pdf. i used two different functions but non of them works. i tried two different cases. to use table and hyperlink. but non of them works too. latest download is text.

I am using a function1 :

download (blobData, contentType, fileName) {

    var element = document.createElement('a');

    element.setAttribute('href', this.preview(blobData, contentType));

    element.setAttribute('download', fileName);

    element.style.display = 'none';

    document.body.appendChild(element);

    element.click();

    document.body.removeChild(element);

  };

I also used this function2:

PageModule.prototype.download = function (data) {

    var bString = window.atob(data);