How can I make, with the use of AppCustomizations.js, a Rest API call to an External system? For example Node Red.

I need just a basic sample.

Regards,

You'd just be writing traditional JavaScript unless there's some additional requirement you are trying to do that isn't communicated here (like calling something in Maximo to send the request to node red). There is a ton of documentation on how to interact with REST APIs using vanilla JavaScript. 

I know. And writing code is exactly what I want. The objective is indeed fetching information collected by a node from Node Red.
Thanks for pointing me to Rest APIs using vanilla JavaScript.

Somehow vanilla script did not came to mind. Was thinking about importing React Native components somehow (there is a lead in the Docker information for that).

I managed to call the Node red endpoint and a json is passed to Mobile as a object.
There are some challenges I have to take (like how to pass a json to an array or variable).

But it looks promising.