This is a FIFA 15 JavaScript (Node) API. The app.js file is an example file that uses the API, so you can use it to easily start developing your custom software / autobuyer.
All API methods are asynchronous, so you have to use a callback for anyone of them. (If you need to synchronize your code, you can easily use events)
Each method have comments in JavaDoc style to let developers easily understand how to use them.
As any other Node app, to install it launch:npm install
Just launch: node app.js