ability to work in headless mode (to don't use document. call)

[terpimost]

Micromark is using decodeNamedCharacterReference here which calls document.createElement('i') here which throws a runtime error in a worker (headless usage).

This is an actual call stack I have

Do you think there is any workaround?

[ChristianMurphy]

This is a bug in your configuration or build tool.
decode-character-reference provides both a web compatible and a worker compatible implementation.
https://github.com/wooorm/decode-named-character-reference/blob/ddb8cdf65a7ce4795c4fc45c8433495377b0f5ea/package.json#L32-L39
Your build tool chose the browser one rather than worker