npm run build cannot be opened with self-written server.js

what does this mean? from the code point of view, server.js is a static resource service running on the server side, so why it should be packaged to dist, but cannot be run on the browser side, am I wrong?

the packaged project needs to be supported by the web container, that is, it needs to run into the web container, such as nginx.
mock data packaged out is invalid. In the case of build, the mock data is not packaged. You must point the address in the server.js to a service address, usually in the form of a proxy.