Ironlad Headless is a Drupal 8 Module that allows CORS requests to the decoupled App. You can install as part of a Drupal website and enable it as you would install and enable any Drupal module. src/config.js will need to be configured to match your particular Drupal instance.
Ironclad React Headless
Ironclad React Headless is a React.js application that is configured to create, delete, update and delete drupal content nodes. Run npm start in the command line to run the application.