XMLHttpRequest (XHR) objects are used to interact with servers. You can retrieve data from a URL without having to do a full page refresh. This enables a Web page to update just part of a page without disrupting what the user is doing.| MDN Web Docs
The Promise object represents the eventual completion (or failure) of an asynchronous operation and its resulting value.| MDN Web Docs
The WHATWG URL API#| nodejs.org
JSON (JavaScript Object Notation) is a lightweight data-interchange| www.json.org
Class: http.Agent#| nodejs.org