I've been toying around with tree-sitter and have seen the potential for a proper, non-regex based highlighter. It's really powerful because it actually parses the text into an AST. With the AST it's possible for example to make variables the same colour everywhere. A function passed as a parameter could be highlighted as a function even in the parameter list.
I'm happy to see that tree sitter highlighting on the web is finally a thing. This seems really solid although the bundle size is a lot.