JSFiddle - React, Tailwind, and code Playground

HTML

<div class="test">1 НОВОЕ</div>
<div class="test">2 НОВОЕ</div>
<div class="test">3 НОВОЕ</div>
<div class="test">13 НОВОЕ</div>

JavaScript

(function () {
    var el = document.getElementsByClassName('test');
    for (var i = 0, l = el.length; i < l; ++i ) {
        el[i].innerHTML = el[i].innerHTML.replace(/(\d+\s+).*/, '$1new');
    }
}())