Comment is not serialized following a single save-load cycle (getSerializedAnnotations, addEditorAnnotation)

[kkoniuszy]

In pdf.js, annotationEditor.addComment() has a hasEditedComment check. Comments that were deserialized from a copy don't pass this because initialText === text.

Because of that, comments are lost in the following scenario:

1. User makes a highlight and adds a comment on it
2. Annotations are serialized using pdfViewerService.getSerializedAnnotations() and saved to external storage.
3. User reloads the document
4. Annotations are fetched from the external storage and loaded using pdfViewerService.addEditorAnnotation()
5. User annotates something else and doesn't touch the comment
6. Annotations are saved
7. User reloads document
8. Annotations are fetched and loaded

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I already have a fix and I'll make a PR in the pdf.js fork. I'm just creating this issue to have something to reference in the commit messages and code comments.

[stephanrauh]

Cool! There's always a use-case I forget to test...

The comment editor is kind of a preview. As far as I can see, Mozilla's started developing it, but they don't show it in the showcase yet (https://mozilla.github.io/pdf.js/web/viewer.html). So I think I was a little too eager when unlocking it. I think it's a calculated, acceptable risk. I only have to make sure I can merge the latest version of pdf.js into my fork.

Update after finding the PR: forget about the text below, you've already done a great job!

So I'd appreciate a minimally invasive PR, ideally with modification markers that help me to solve merge conflicts. That'd be

// #3116 modified by ngx-extended-pdf-viewer
... (your modification is here)
// #3116 end of modification by ngx-extended-pdf-viewer

I'm not dogmatic, I can add that myself if you're in a hurry, but it'd make my life easier.

[stephanrauh]

I just found your PR. It matches my wish list perfectly - and you did it before I asked you to do! Thank you so much!

At the moment, I'm running low on time, but I'll try to test and merge your PR ASAP.