Reuse XMLHttpRequest object or create a new one?

Question

I searched stackoverflow but got contradictory answers:

Why should I reuse XmlHttpRequest objects?

Ajax-intensive page: reuse the same XMLHttpRequest object

Answer 1

From MDN Web Docs:

If the httpRequest variable is used globally, competing functions calling makeRequest() can overwrite each other, causing a race condition. Declaring the httpRequest variable local to a closure containing the AJAX functions avoids this.

Source: https://developer.mozilla.org/en-US/docs/Web/Guide/AJAX/Getting_Started