App-Tutorial | This tutorial will walk you through building an add-on | Runtime Evironment library

We'll start the tutorial by setting up the back-end of the add-on.
Download and install the latest stable version of Node.js.
Download and install Docker Desktop.
When your partner account is set up and your add-on has been approved, the Neto team will provide you with a client ID and a client secret key. Keep your secret key private, do not store it in your code. Instead, use them as environment variables that are available when the code runs.
Create a new file called index.js. This will serve as the entry point to your application. Add the following:.
We'll use create-react-app to quickly setup a widget that can be rendered on your sandbox store. Navigate out of your back-end project folder and run the following:.
Open src/App.js and remove the existing content. Add the following:.
We define two state components, the active order that we are showing in the widget and the list of orders.
In the first effect we fetch orders from our server application and save them from state. Because we supply no dependencies in the effect this effect only runs when the component mounts onto the page.
In the second effect we setup an interval that loops through the list of orders that were returned from our server application and sets a single one as the activeOrder at a time. Because this effect relies on the orders that we fetched from the server application, we supply orders as a dependency.
Finally, we render a small widget if there is an active order that says: Someone in {city} bought {name}!