I have a big application with different features. What I want to know exactly is that should I overwrite all setState() functions that I have used with redux ? or in some cases I have to use redux instead ?
I mean is it bad to use redux for a simple setSate action ?
It is ultimately up to you, but Redux is pitched as "global state management", which I interpret as "the state of the app".
Generally, the way I would build my state out would be to have Redux handle the data of logical/business structures (e.g. data coming from APIs), and as such I would pass in props to the components that use said data.
Once inside the component, I would use the component state to allow the component to manage its own logic for the things that it is concerned about, such as logic needed to conditionally render things or optimistic updates.
Some have even completely removed Redux from their applications with the advent of GraphQL + Apollo, allowing them to have server-side computations for what the UI would traditionally display (e.g. providing a boolean like hasComment) so that the UI doesn't have to perform that computation (backend is usually faster at these computations, too) and simply state {hasComment && <Comment />}. Another advantage of this approach is that other UIs could use hasComment without needing to implement duplicate logic.
