jQuery is great. Not only for its famous DOM manipulation but also for its extended functionalities, ajax is one of them. But when you use some libraries like React, you won’t need jQuery at all. But still you need to make an ajax call, how to deal with it?
There are tons of libraries which you can use. But just a special one you should pay attention, Fetch API, a living standard, and will someday be implemented by every modern browser. In fact, the latest version of most browsers have all supported this API. Including Chrome(Desktop/Android), Firefox, Opera and Edge. Let’s say how fancy it could be :) We’ll see it in a high abstract view first, then break into pieces. So you can learn it in a very fast pace.