How to create fragemented file with mp4box.js

Question

I know that you can do this to create a dash file:

MP4Box -dash 10000 -frag 1000 -rap -single-segment test.mp4

But what would the equivalent (giving a filename, and converting it to a dash file) be in javascript where I link mp4box.js via cdn?

I've tried looking at the docs, and I'll continue looking at them, but I know for sure they did not show how to use mp4box with js in the most efficient way and it just has me stumped.

I'm looking at this here because it seems like this is part of what I have to use, but it isn't even containing everything it needs for it to work:

var mp4box = MP4Box.createFile();
mp4boxfile.onReady = function(info) {
  ...
  mp4boxfile.onSegment = function (id, user, buffer) {}
  mp4boxfile.setSegmentOptions(info.tracks[0].id, sb, options);  
  var initSegs = mp4boxfile.initializeSegmentation();  
  mp4boxfile.start();
  ...
};

The docs - > https://github.com/gpac/mp4box.js/

If anyone has any ideas that would be great.