I'm attempting to utilize the Blob function to generate a file from information transmitted via a server call, encoded in base64. The initial file is an Excel spreadsheet with a length of 5,507 bytes. After applying base64 encoding (including newlines), the resulting size becomes 7,441 bytes. By utilizing the command line base64 tool, I can successfully recreate an exact duplicate of the original file through its base64 version:
% base64 file.xlsx > file.enc
% base64 -d file.enc > copy.xlsx
% cmp file.xlsx copy.xlsx
% file --mime-type copy.xlsx
copy.xlsx: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
In my TypeScript code, I have implemented the following:
import * as dld from 'file-saver';
const contentType = 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet';
const data = atob(content)
const contentBlob = new Blob([data], { type: contentType });
dld.saveAs(contentBlob);
I have validated that the binary data (assigned to the variable data above) at least shares the same initial byte sequence as the binary content found within the original file. However, upon creating the file, it turns out to be 7,729 bytes long and possesses a MIME type of application/zip, deviating from the expected result of 5,507 bytes. What could I possibly be overlooking in this scenario? Is there something distinct that needs to be done in order for me to generate an accurate client-side replica of the file?