Is there any specific usage advantage/disadvantage in using createSlice() over createReducer() other than the boilerplate reduction

Question

I've referred to a couple of links, including https://github.com/reduxjs/redux-toolkit/issues/81. But it's answered long back in 2019 and not quite helpful.

Answer 1

Since createSlice uses createReducer internally, the short answer is no, the main advantage is boilerplate.

Keep in mind though that in createReducer and createSlice's extraReducers we recommend that you should use the builder notation and not the object map notation as the latter is impossible to simply port over to TypeScript later and advanced stuff like matchers are significantly more easy to use with the builder notation.

Also, I can't think of a single reason to use createReducer instead of createSlice as long as your resulting reducer has at least one single action type that should be created alongside the reducer.