TextCritical.net

• Open work
• Press Shift+right several times; note that it moves several chapters

Uncaught TypeError: Cannot read properties of null (reading 'next_chapter')

Questions:

• What is the related stack trace?
  • readingMenuBar::upHandler()
• Is the handler not getting removed properly?
• Is the problem due to not having an empty array of dependencies after useEffect?
  • https://www.pluralsight.com/guides/event-listeners-in-react-components
  • This gets rid of the multiple addHandler() registrations but it also breaks it
• When does useEffect()'s cleanup get called?
• Does this improve if I only add the handler if both goToNextChapter and goToPriorChapter are set?
  • No change
• Does this work if I keep the handler around and only apply it if doesn't yet exist?
  • No change

• upHandler() is getting called several times
• addHandler() gets called 7 times on a normal load
  • removeHandler() gets called 6 times
• It looks like the handlers are not getting removed
  • getEventListeners(window).keyup.length
  • These keep increasing

• I wasn't deregistering the handlers correctly