I have add the following code to local copy to solve this issue by myself, thanks.

(new Date().toISOString().split('T')[0])+"-> "

@fujohnwang thank you for letting me know that you've fixed the issue for yourself. Would you like to create a pull request with your changes? Then I could take a look and include it to this extension 🙂

I could also add an option which could enable/disable this feature through the user settings 👍

@PKief sorry, I just modify the local source code under ~/.vscode, since I don't have enough skills on vscode extension dev, I have simply browsed the source and add date string under:

if(!r(s))e.edit(e=>{e.insert(new o.Position(s.lineNumber,a.pos),(t&&!a.bullet?n+" ":"")+"[ ] "+(new Date().toISOString().split('T')[0])+"-> ")})})

vscode-markdown-checkbox/src/createCheckbox.ts maybe.

I think, if you can provide config options for the date format and disable/enable, that will be great for all extension users ;0)