JSFiddle - React, Tailwind, and code Playground

HTML

<div id="editor" contenteditable="true">Some test text, please select some then press the button</div>
<a onclick="document.execCommand('bold',false,null);" unselectable="on"><div unselectable="on" >This button destroys selection</div></a>

<a onclick="document.execCommand('bold',false,null);" unselectable="on">This button keeps the selection</a>

CSS

a,span
{
 display: inline-block;
 border: 1px solid grey;   
}