How to make a simple single page application?

Question

JavaScript

The bottom line is this: you need to make a SPA. So that when you switch to another url, only part of the page changes. With PS indexing and other goodies.
Under the hood of RoR 4.2
Of course I understand that the question sounds strange due to the presence of a zoo of frameworks tailored for this business. But is it possible to do without them? Because I need only the SPA functionality, without pulling up unnecessary goodness.
Turbolinks, Pjax and the like please do not offer. They swam.

Answer 1

jquery + history API