JSFiddle - React, Tailwind, and code Playground

HTML

<div class="comments">comment 1** is good**</div>
<div class="comments">comment 2**is bad**</div>

JavaScript

function markdown(markdownable){
            
var boldMatch = markdownable.match(/\*\*[A-Za-z0-9]+\*\*/gim), boldReplace = boldMatch.replace(/\*\*[A-z0-9]+\*\*/gim, '<span style="font-weight:bold;color:blue;">'+boldMatch+'</span>'),
                     
markdownable = markdownable.replace(boldMatch, boldReplace);     
markdownable = markdownable.replace(/\*\*/gi, "");

 return markdownable;
}
        
$('.comments').each(function(){
    
var markdownable=$(this).html(), comments=markdown(markdownable);
});