JSFiddle - React, Tailwind, and code Playground

HTML

{: 5 + 5 :}

JavaScript

console.clear();
var view = document.querySelector('body').innerHTML;
var fn = '' + new Function('return 5 + 5')();
var exp = '5 + 5';
var	pattern = new RegExp(
  '{: ' + exp + ' :}', 'g'
);
console.log(pattern);
view = view.replace(pattern, '');
console.log(view.search(pattern));
document.querySelector('body').innerHTML = view;