New callback for capturing changes on Codeview

[lqez]

What does this PR do?

• This provides a new callback onChangeCodeview for capturing changes on Codeview. (also works with CodeMirror)

What are the relevant tickets?

• Firing onChange event when cmEditor is changed #1267

Checklist

• added relevant tests
• didn't break anything

[DennisSuitters]

@lqez WIll this allow us to dynamically update each of the views if visible? For e.g. If each view is visible side by side, and content in code view is edited and in real time make changes in normal view, like edit code and see a preview while editing.

[lqez]

@DiemenDesign Yes, I think so either. :)

[yxl]

Thanks for providing the fix.

Should we also fire onChange event when codeview changes? It is straightforward to let onchange callback capture codeview changes and less error prone for newcomers to properly set up onchange callback.

It is likely that people forget to add onChangeCodeview callback when watching the content changes.

[lqez]

We'd discussed this before, and chose to separate two dedicated events.
I worried about pre-created a lot of onChange callbacks what originally expected getting events only in WYSIWYG view. I also agree with you but explicit and consistency are more important than others.

Thank you for your kind feedback, @yxl.

[f1yn]

Please merge this upstream