What is the primary function of Server.js in SFCC?

The primary function of Server.js in Salesforce Commerce Cloud (SFCC) is to manage server-side logic. This file is crucial for the application as it serves as the entry point for server-side request handling within the platform. It allows developers to define custom routes, handle incoming requests, and implement business logic that will respond to these requests. By utilizing Server.js, developers can process server-side operations, such as executing controller actions, integrating with the SFCC framework, or communicating with different models, thus allowing for the creation of dynamic responses based on user actions or other criteria.

Other options describe different functionalities that are not directly managed by Server.js. Client-side interactions are typically handled through client-side JavaScript, configurations across a cartridge are often managed through specific configuration files or settings, and caching for static assets involves different mechanisms and settings within the platform that are separate from the server logic defined in Server.js.