JSFiddle - React, Tailwind, and code Playground

HTML

<form id="test" method="post">
    <input type="text" id="t">
    <input type="submit" value="convert!">
</form>

JavaScript

function string_to_slug(str) {
  str = str.replace(/^\s+|\s+$/g, ''); // trim
  str = str.toLowerCase();
  
  // remove accents, swap ñ for n, etc
  var from = "àáäâèéëêìíïîòóöôùúüûñç·/_,:;";
  var to   = "aaaaeeeeiiiioooouuuunc------";
  for (var i=0, l=from.length ; i<l ; i++) {
    str = str.replace(new RegExp(from.charAt(i), 'g'), to.charAt(i));
  }

  str = str.replace(/[^a-z0-9 -]/g, '') // remove invalid chars
    .replace(/\s+/g, '-') // collapse whitespace and replace by -
    .replace(/-+/g, '-'); // collapse dashes

  return str;
}
$(document).ready(function() {
    $('#test').submit(function(){
        var val = string_to_slug($('#t').val());
 				if (val.substr(val.length - 1) == '-') {
        	val.slice(0,-1)
        }
        alert(val);
        return false;
    });
});