Sort textarea unique

index.html

<a href="javascript:(function(){Array.from(document.querySelectorAll('textarea')).map(function(b){var a=document.createElement('div');var d=document.createElement('button');d.textContent='↑';d.addEventListener('click',function(f){f.preventDefault();b.value=Array.from(new Set(b.value.split('\n'))).sort().join('\n')});var c=document.createElement('button');c.textContent='↓';c.addEventListener('click',function(f){f.preventDefault();b.value=Array.from(new Set(b.value.split('\n'))).sort().reverse().join('\n')});a.appendChild(d);a.appendChild(c);b.parentNode.insertBefore(a,b)})})();">Sort textarea unique</a>

sort_unique_raw.js

(function() {
Array.from(document.querySelectorAll('textarea')).map(function(ta) {
  var container = document.createElement('div');

  var asc = document.createElement('button');
  asc.textContent = '↑';
  asc.addEventListener("click", function(e) {
    e.preventDefault();  
  ta.value = Array.from(new Set(ta.value
    .split(/\n(?==.+=$)/m)
    .map(section => {
      const [heading, body] = section.split(/(?<==)\n/);
      return `${heading}\n${body.split('\n').sort().join('\n')}`;
    })
    .join('\n');});
  

  var dsc = document.createElement('button');
  dsc.textContent = '↓';
  dsc.addEventListener("click", function(e) {
    e.preventDefault();
  ta.value = Array.from(new Set(ta.value
    .split(/\n(?==.+=$)/m)
    .map(section => {
      const [heading, body] = section.split(/(?<==)\n/);
      return `${heading}\n${body.split('\n').sort().reverse().join('\n')}`;
    })
    .join('\n');});

  container.appendChild(asc);
  container.appendChild(dsc);
  ta.parentNode.insertBefore(container, ta);
})
})()