JavaScript util to saveData (download as a browser attachment), taking data and allowing output filename.

save-data-as-attachment.js

const saveDataAsAttachment = (() => {
  const a = document.createElement('a');
  a.style = 'display: none';
  document.body.appendChild(a);

  return (data, fileName) => {
    const blob = new Blob([data], {type: 'octet/stream'});
    const url = window.URL.createObjectURL(blob);
    a.href = url;
    a.download = fileName;
    a.click();
    window.URL.revokeObjectURL(url);
  };
})();