downloadFile.js

const b64toBlob = (b64Data, contentType = "", sliceSize = 512) => {
  const byteCharacters = atob(b64Data);
  const byteArrays = [];

  for (let offset = 0; offset < byteCharacters.length; offset += sliceSize) {
    const slice = byteCharacters.slice(offset, offset + sliceSize);

    const byteNumbers = new Array(slice.length);
    for (let i = 0; i < slice.length; i++) {
      byteNumbers[i] = slice.charCodeAt(i);
    }

    const byteArray = new Uint8Array(byteNumbers);
    byteArrays.push(byteArray);
  }

  const blob = new Blob(byteArrays, { type: contentType });
  return blob;
};

export const downloadFile = (data, fileName, isZip) => {
  if (window.navigator && window.navigator.msSaveOrOpenBlob) {
    window.navigator.msSaveOrOpenBlob(
      b64toBlob(data, "application/pdf"),
      fileName
    );
  } else {
    const linkSource = `data:${isZip?`text/plain`:`application/pdf`};base64,${data}`;
    const downloadLink = document.createElement("a");
    downloadLink.setAttribute("href", linkSource);
    downloadLink.setAttribute("download", fileName);
    downloadLink.href = linkSource;
    downloadLink.download = fileName;
    downloadLink.click();
  }

  return;
};