Hi Tarek,
I have converted some libraries to use in XFA forms, but not this big. Should be easier in Reader DC which supports Uint8Array as well as some other ES5 things like JSON.parse and new Date('yyyy-mm-dd'). We don't have a Blob object, but maybe that would need to change to a Data object anyway, I only had a very quick look.
A common problem converting JavaScript code is in Reader we can't override the toString or valueOf methods so we need to come up with slightly difference names (I use _valueOf), it gets tricky as these can be implicitly called depending on if the context is string or numeric, so is easy to miss.
I'm not sure what I meant by my comment now, might have been thinking it would be clumsy for the end user or difficult to code.
Good luck
Bruce