The give-it-a-REST project is a lightweight php code library to make it easier to add WordPress rest API to themes and plugins.

It takes an Object Oriented approach.

The steps are:

* Establish your endpoint namespace
* Establish your endpoint version
* Build a Resource Handler to match each of the resources you wish to provide via REST derived from the abstract base class WpEpResourceHanlder
* In your derived class implement, get, put, post, delete and patch methods as appropriate.
* Use the add_route method to add the routes to your resources
* Use the init_route method to initialize those routes

The class OptionAsResource shows how to implement get/post/put/and delete

The file test.js shows how to use the REST API using jQuery ajax
If you install the plugin you will see a new menu item in Settings - REST Test

The Rest Test page allows you to test the REST calls from test.js