I know the Fetch API is probably going to replace AJAX, and soon.
I also know that learning jQuery is less important now than it has been for a number of years.
However, jQuery Ajax commands are very useful, compact, and still necessary for many APIs. So these ready-to-use code snippets for every day can really come in handy when you just need to get some external data into your HTML quickly and easily.
The snippets cover
$.serialize(). They do not cover
$.ajax(), which essentially does everything, but with more lines.