JSFiddle - React, Tailwind, and code Playground

HTML

<a href="javascript:void(0);" onclick="openOrFocus('http://jsfiddle.net/k3t6x/2/', 'window1')">Window 1</a><br />
<a href="javascript:void(0);" onclick="openOrFocus('http://jsfiddle.net/KR6w3/1/', 'window2')">Window 2</a><br />

JavaScript

window.openOrFocus = function(url, name) {
    if (!window.popups)
        window.popups = {};
    if (window.popups[name])
        window.popups[name].close();
    window.popups[name] = window.open(url, name);
}