Function wrapReducer

test/typescript/enhancers.ts:60–70

(
        reducer: Reducer<S, A, PreloadedStateToWrap>
      )

      preloadedState?: PreloadedState | undefined
    ) => {
      function wrapReducer<PreloadedStateToWrap>(
        reducer: Reducer<S, A, PreloadedStateToWrap>
      ): Reducer<S & ExtraState, A, PreloadedStateToWrap & ExtraState> {
        return (state, action) => {
          const newState = reducer(state, action)
          return {
            ...newState,
            extraField: 'extra'
          }
        }
      }
      const wrappedPreloadedState = preloadedState
        ? {
            ...preloadedState,