Markdown Preview update sometimes breaks down in the restored preview

[yhatt]

Version of Marp Tool

Marp for VS Code v1.5.1

Operating System

Windows

Environment

• OS version: Windows 10
• VS Code version (Marp for VS Code): v1.67-insider

How to reproduce

1. Create a new Markdown file (Don't need that is Marp document)
2. Type in some characters and open preview
3. Choose "Developer: Reload Window" from the command palette.
4. Add new characters to Markdown one by one

Expected behavior

Replaces the current Markdown preview to the updated contents.

Actual behavior

The outdated preview contents will keep from the second updation, and new contents will insert to the last of preview.

Additional information

I guess Marp extension is causing failed updation of the preview because could not reproduce that if disabled Marp extension.

It is especially reproducible when edited Markdown at the same timing as showing restored preview. (At that time, I think script for VS Code's preview has been loaded, but a contribution script from Marp may not be loaded yet)

[eyssette]

Same problem here.

Marp for VS Code v1.5.1
Operating System : Mac
Environment : Mac OS Monterey 12.2.1

[yhatt]

I finally found out an accidental collision of minified global variable, between Marp's script for preview and VS Code's preview script.

In the context of morphdom, used by VS Code for incremental updation of DOM, a global variable ELEMENT_NODE from morphdom must be 1. It has been defined as minimized global variable j in Markdown preview.

On the other hand, Marp's minified preview script also has defined j global variable as Object.defineProperty. If Marp script was loaded after VS Code's preview script, Marp will break morphdom by accidential overloading!

Fortunately it is easy to fix: Set format constructor option for EsbuildMinifiyPlugin as 'iife'. (privatenumber/esbuild-loader#139 (comment))