Node.js manipulate blob in server

Tn client side, I am encoding a wav file into an array of ArrayBuffers, i am packing them as single blob, and uploading it to server as a file.

Now this is where I am getting struck, I have to dissect the blob on server side and decode back to wav( i am able to successfully do this on client side ) ,

how do I turn the file into blob and then manipulate it, I am assuming 'fs' would help me convert file back to blob, but i am not finding any material for manipulating blob in node.js.