[redux-toolkit] "reducer" is a required argument, and must be a function or an object of functions that can be passed to combineReducers

Uncaught Error: "reducer" is a required argument, and must be a function or an object of functions that can be passed to combineReducers

발생상황

index.js에서 ReduxProvider를 씌우니까 발생

원인

configureStore 사용시에 reducer를 객체로 넣지 않아서 발생

configureStore(reducer)

해결

recuer를 객체로 넣어준다

configureStore({reducer})