JSFiddle - React, Tailwind, and code Playground

HTML

<div>
  <p id="inp1">1</p>
</div>

<div>
  <p id="inp2">2</p>
</div>
<div>
  <a href="#" onclick='return replaceElements(inp1, inp2);'>Поменять местами</a>
</div>

JavaScript

function replaceElements(elem_1, elem_2){
  var next = elem_1.nextElementSiblings,
        parent_1 = elem_1.parentNode,
        parent_2 = elem_2.parentNode
  ;
  
  parent_2.insertBefore(elem_1, elem_2);

  if(next){
     parent_1.insertBefore(elem_2, next);
  }else{
     parent_1.appendChild(elem_2);
  }

}