JSFiddle - React, Tailwind, and code Playground
HTML
<textarea cols="100" rows="20" id="decoder"></textarea>
<input type="button" onclick="htmlDecode()" value="Decode">
JavaScript
function htmlDecode(){
var input = document.getElementById('decoder');
var inputvalue=input.value;
var e = document.createElement('div');
e.innerHTML = decodeURIComponent(inputvalue.replace(/\+/g, " "));
input.value=e.childNodes[0].nodeValue.toString();
}