Why do you need this library? Google Chrome (as of version 64) can not estimate the total download size of XMLHTTPRequests when content-encoding: gzip is set, even if the content-length header is set.

The foundation that makes AJAX possible is the communication layer with the server. The most complete option for performing this communication is the JavaScript XMLHttpRequest object. If ...

Thanks to your bug report I think I have a fix for this rolled out now! I did a review of all calls to XMLHttpRequest in the project (they are all in components/session.js) and there was one place ...