JSFiddle - React, Tailwind, and code Playground

HTML

<textarea id="b">
    <meta charset="utf-8">

    <title>Some Meep meta, awesome</title>




    <-- some comment here -->
    <meta name="someMeta, yay" content="meep">

</head>
</textarea>

CSS

#b {
    width: 300px;
    height: 200px;
}

JavaScript

var ta = document.getElementById('b');
ta.innerHTML = ta.innerHTML.replace(/\n{2,}/g, '\n');