Is there a tool ( application, online service ) that helps writing the ugly formatting MathJax + MHchem code ?

I do not mean a WYSIWYG editor like the onsite one, or stackedit.io (MathJax only ). I mean the help with actual writing the formatting metacharacters. Like macro expansions, buttons for formattings or similar.

As the requirements for a fancy, typographically correct text does not seem to be balanced with the support of available editor tools.