As a new iOS user, I'd love to see some "less than apple approved" things going on the iOS platform. Can we get a list going?

Describe the bug
When exporting annotation with Flashcard, the JSON line is undefined

    },
    undefined,
    {

To Reproduce
Steps to reproduce the behavior:

1. Annotate a line of text
2. Add a Flashcard with data on back and front
3. Export annotation as JSON
4. Search "undefined" you should get to that badly exported entry

Expected behavior

Fla

Task:

• Update events 'list' to include new field: pageChanged = 'pageChanged';
• find all the places pageChanged is used, and point it to its new reference (events.pageChanged)
• Make sure that the event BookReader:pageChanged is emitted when changing the page
• Make sure all tests pass

https://github.com/internetarchive/bookreader/blob/master/src/js/BookReader/events.js

Please report any duplicate entries here. Don't open separate issue for every duplicate.