[miragecraft]

I disagree that you shouldn’t use document.write for <script> and <style> tags, as it’s the only way to force dynamically inserted script to run in a parser-blocking manner during parsing, and to prevent flash of unstyled content (FOUC) for dynamically inserted styles.

Yes it’s slower, but does it matter for your specific use case? Async scripts are harder to reason about, esp if you have nested templates. FOUC is also a much bigger and more noticeable problem than the tiny delay to parse the CSS snippets.

Forcing scripts to be parser-blocking is also needed if you want to nest document.write, to ensure it is writing to the correct location in the document.

I created an HTML includes library that utilizes document.write extensively: https://miragecraft.com/projects/x-include