const initialState = {
previousLocation: null,
currentLocation: null,
};
const routerLocations = function (state = initialState, action) {
  const newstate = { ...state };
  switch (action.type) {
      case "@@router/LOCATION_CHANGE":
          newState.previousLocation = state.currentLocation;
          newState.currentLocation = action.payload;
          return newState
    default:
      return state;
  }
}

export default routerLocations;

"react-router": "^4.2.0",
"react-router-dom": "^4.2.2",
"react-router-redux": "^4.0.8",