Improve article-editing experience to not lose unsaved changes

I'm sure there are a number of solutions that could be implemented to address the issue of losing edits in Guide, so I'm going to provide context of what I've experienced and propose a few solutions that I think could improve the experience.

My most recent issue: After making an hour's worth of changes to an existing article, I lost all of those changes. My power went out briefly and, concerned that I’d lose my work, I selected the source code button so that I could copy the current state of the article and paste it later if needed. Instead of an error pop-up (or literally any other experience), I got a full page error that gave me the exact experience I was attempting to avoid. There was no way to go back to my changes.

In past instances, I’ve lost hours upon hours of hard work after accidentally triggering the Back or Refresh button in my Firefox browser or with my Mac’s trackpad, as well as after updating table properties within the Guide editor, which triggered another full-page error and caused me to lose everything.

Here are a couple of enhancements that I know would drastically improve the editing experience and prevent this issue from occurring:

• Implement a "drafting" mode or an "auto-save" functionality so that refreshing the page doesn't lose all unsaved work
• Implement a pop-up dialog when an error occurs, which would allow users to exit the dialog and return to editing the article

Please fix this terrible UX. I know I'm not the only one who has experienced the same overwhelming frustration of this problem.