How to write a plugin that handles import to *.html files?

[miguel-leon]

I created and added (installed?) a plugin with enforce: 'pre', with which I hope to resolveId or load ids that end with .html, instead of whatever vite does with them.
To my understanding, with enforce: 'pre' my plugin will run first than "Vite core plugins", yet I get an error: [vite] (client) Pre-transform error: Failed to parse source for import analysis because the content contains invalid JS syntax. You may need to install appropriate plugins to handle the .html file format, or if it's an asset, add "**/*.html" to assetsInclude in your configuration..

Do I need to configure something else or is this a bug?

Also, these .html ids that I import (in js/ts files), are not passed by transformIndexHtml in vite dev, but are passed during vite build.
Why the difference? I can't find documentation about this.

Thank you.