JavaScript URLs to clickable HTML links

<p id="preview-text"></p>
<textarea rows="10" cols="75" id="text-val">Online HTML Code Generator CSS, JavaScript, PHP, JQuery, https://www.html-code-generator.com/  Multi Color Text Generator www.html-code-generator.com/html/rainbow-text-generator</textarea>
<button id="convert">Convert</button>

<script>
document.getElementById("convert").onclick = function(){
  let text = document.getElementById("text-val").value;
  let link_attributes = {
    target: '_blank',
    class: 'mylink',
    rel: 'nofollow noopener'
  };
  let result = convert_url(text, link_attributes);
  document.getElementById("preview-text").innerHTML= result
}
</script>