The W3 announced that they intend to deprecate the BlobBuilder API in preference for the new Blob API.
If I am already using BlobBuilder in a JavaScript app, how can
Passing an ArrayBuffer to the Blob constructor appears to be deprecated, so:
var dataView = new DataView(arrayBuffer);
var blob = new Blob([dataView], { type: mimeString });
var blob = new Blob([arrayBuffer], {type: mimeString});
From what the specs says it should be as simple as this. Just check the examples of the page you posted.
var blob = new Blob(arrayBuffer);
[Constructor, Constructor((ArrayBuffer or Blob or DOMString)