busboy | A streaming parser for HTML form data for node.js | Runtime Evironment library

PayloadTooLargeError: request entity too large
   at readStream (C:\Users\User\AppData\Roaming\npm\node_modules\firebase-tools\node_modules\raw-body\index.js:155:17)
   at getRawBody (C:\Users\User\AppData\Roaming\npm\node_modules\firebase-tools\node_modules\raw-body\index.js:108:12)
   at read (C:\Users\User\AppData\Roaming\npm\node_modules\firebase-tools\node_modules\body-parser\lib\read.js:77:3)
   at rawParser (C:\Users\User\AppData\Roaming\npm\node_modules\firebase-tools\node_modules\body-parser\lib\types\raw.js:81:5)
   at Layer.handle [as handle_request] (C:\Users\User\AppData\Roaming\npm\node_modules\firebase-tools\node_modules\express\lib\router\layer.js:95:5)
   at trim_prefix (C:\Users\User\AppData\Roaming\npm\node_modules\firebase-tools\node_modules\express\lib\router\index.js:317:13)
   at C:\Users\User\AppData\Roaming\npm\node_modules\firebase-tools\node_modules\express\lib\router\index.js:284:7
   at Function.process_params (C:\Users\User\AppData\Roaming\npm\node_modules\firebase-tools\node_modules\express\lib\router\index.js:335:12)
   at next (C:\Users\User\AppData\Roaming\npm\node_modules\firebase-tools\node_modules\express\lib\router\index.js:275:10)
   at urlencodedParser (C:\Users\User\AppData\Roaming\npm\node_modules\firebase-tools\node_modules\body-parser\lib\types\urlencoded.js:100:7)

These are my code files

index.js

Javascript library for Microsoft Office add-ins allows you to get raw content of the DOCX file through getFileAsync() api, which returns a slice of up to 4MB in one go. You keep calling the function using a sliding window approach till you have reed entire content. I need to upload these slices to the server and the join them back to recreate the original DOCX file.

I'm using axios on the client-side and busboy-based express-chunked-file-upload middleware on my node server. As I call getFileAsync recursively, I get a raw array of bytes that I then convert to a Blob and append to FormData before posting it to the node server. The entire thing works and I get the slice on the server. However, the chunk that gets written to the disk on the server is much larger than the blob I uploaded, normally of the order of 3 times, so it is obviously not getting what I sent.

My suspicion is that this may have to do with stream encoding, but the node middleware does not expose any options to set encoding.

Here is the current state of code:

Client-side

EDIT_v1:
Been trying to follow this post using busboy as the parser: Calculate a file hash and save the file. I took an example from the busboy docs and adabpted it with an answer from the post:

** : TypeError: auth.getAuth(...).verifyIdToken is not a function **

This is my auth code:

To me, this seems completely random, as I have tried this with a dozen files of varying size and content type (audio/flac & audio/x-flac), and the results have been inconsistent. Some files will, however, not work at all, even if I attempt to parse them many times over. Whereas, certain files can be parsed and uploaded, given enough attempts?

Is there some error that I fail to deal with in the 'file' event? I did try to listen to the file.on('error', => {}) event, but there were no errors to be found. Other answers suggest that the file stream must be consumed for the 'close' event to proceed, but I think that file.pipe(fs.createWriteStream(fileObject.filePath)); does that, correct?

Let me know if I forgot to include some important information in my question. This has been bothering me for about a week now, so I am happy to provide anything of relevance to help my chances of overcoming this hurdle.

When I use: import fetch from "node-fetch";

I have the following error: