To consume a Node.js service in an SAPUI5 application, you need to define the variable for the exposed service in the requires section of the HTML5 module in the mta.xml file. This way, you can specify the dependency of the SAPUI5 application on the Node.js service and bind them together. The requires section allows you to reference a resource or a module that provides a service or a capability that your module needs.
You can also define additional properties and parameters for the required element, such as the name of the variable that holds the service URL. References: The MTA Development Descriptor, The MTA Deployment Descriptor, Developing Multi-Target Applications