export interface WelcomePopupState { welcomePopupState : string ; } export interface WelcomePopupAction { type : any ; className ? : string ; } const initialState = { welcomePopupState : 'is-active' } ; export const welcome = ( state = initialState , action ) => { switch ( action . type ) { case 'SET_WELCOME_POPUP_STATE' : return state = Object . assign ( { } , state , { welcomePopupState : action . className } ) ; default : return state ; } } ;