Introduction of a new module?

Question

Node.js

Hello! There is a project with the following functionality: authorization / registration, creation of components in a table (a la todo), search in this table, and so on. The task is to write a chat module with functionality: sending messages, the ability to attach files (mainly .doc), + screenshots (photos), the ability to save a list of dialogs from users already registered on the service.
Question: Can this be implemented in the same project where the service itself is (write the chat logic in redux interfering with the service logic) or is it better to implement it in a separate project, and then connect it (then the question is writing an API for the chat)?
The same applies to the back part on the node: Is it also possible to shove everything into the service routes or can it be decompressed?

Answer 1

write chat logic in redux interfering with service logic

Why bother? You can write in separate files in the actions, reducers and components directories. You can put it in a separate folder as feature. Can be made a separate entry point. It can be loaded in a separate chunk on demand.
You should know better what is best for you. There are many ways.
The same goes for the part on node.
Yes, it can be beautifully divided into modules, just like the client part.