Create a pseudo-link to a file in order to trigger browser prompt for file download.

download-file.helper.ts

/**
 * Download a file from a Blob with explicitly set MIME type.
 * @param fileBlob The input Blob.
 * @param mimeType A string representing a conform MIME type (see RFC 6838).
 * @param outName A string for the downloaded file name.
 */
 export const downloadFile = (fileBlob: Blob, mimeType: string, outName: string): void => {
  // explicitly set blob mime-type
  const blob = new Blob([fileBlob], { type: mimeType });

  // IE compatibility
  if (window.navigator && window.navigator.msSaveOrOpenBlob) {
    window.navigator.msSaveOrOpenBlob(blob);
    return;
  }

  //const createObjectURL = (window.URL || window.webkitURL || {}).createObjectURL || function(){};
  const download = window.URL.createObjectURL(blob);
  const link = document.createElement('a');
  link.setAttribute('href', download);
  link.setAttribute('download', outName);
  link.dispatchEvent(new MouseEvent('click', { bubbles: true, cancelable: true, view: window }));

  // avoid memory leak
  setTimeout(function () {
    // for Firefox it is necessary to delay revoking the ObjectURL
    window.URL.revokeObjectURL(download);
    link.remove();
  }, 100);
}