WIP: Version switcher

[davepagurek]

Here's an experiment to see what a version picker could look like on the web editor.

What works so far:

• Updating the version when index.html is edited seems stable and not super laggy!
• The logic of detecting a version only if we see exactly one script tag that we recognize seems to feel right

Screen.Recording.2025-02-06.at.8.24.27.PM.mov

What does not work so far, if I uncomment the code to actually replace the contents:

• After replacing, dom.documentElement.outerHTML doesn't have quite the same formatting as before (e.g. the DOCTYPE tag is gone) -- maybe there's another attribute I can use, need to experiment more
• Is there a good way to force CodeMirror to update when this happens? I have a commented-out attempt to replace its contents when the props change and are different than the current content, but this also has the effect of preventing people from typing.

Screen.Recording.2025-02-06.at.8.17.15.PM.mov

[welcome]

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