Ruby Style formatter

HTML

<pre contenteditable>
</pre>
<select>
    <option>hash style</option>
    <option>JSON to hash</option>
</select>
<button>Apply</button>

JavaScript

(function () {
  'use strict';
  var inputEl = document.querySelector('pre'),
    select = document.querySelector('select'),
    button = document.querySelector('button');
    
    button.addEventListener('click', function (event) {
      var type = select.value;
    
        if (type == 'hash style') {
          inputEl.textContent = inputEl.textContent.
              replace(/:([\w]+)(\s)*=>/gm, '$1:');
        } else if (type == 'JSON to hash') {
          inputEl.textContent = inputEl.textContent.
              replace(/"([^"]*)"(\s)*:/gm, '$1:');
        }
    });
})();