React Redux Undefined Object Passed into the Reducer

I'm working on my first React Redux application in typescript and I have a peculiar error in that the object that the reducer is receiving is 'undefined'.

types.ts

//Action typesexport const ADD_FAVOURITE = 'ADD_FAVOURITE'export const REMOVE_FAVOURITE = 'REMOVE_FAVOURITE'//Add favourite actioninterface addFavouriteAction {  type: typeof ADD_FAVOURITE,  favourite: ImageThumbnail}//Remove favourite actioninterface removeFavouriteAction {  type: typeof REMOVE_FAVOURITE,  id: string}export type favouriteActionTypes = addFavouriteAction | removeFavouriteActionexport interface favouriteState {  favourites: ImageThumbnail[]}export const initialState: favouriteState = {  favourites: []}export type rootState = ReturnType<typeof favouriteReducer>

store.ts

export const rootReducer = combineReducers({  favouriteReducer})const store = createStore(rootReducer)export default store

actions.ts

export function addFavourite (image: ImageThumbnail): favouriteActionTypes {  return {    type: ADD_FAVOURITE,    favourite: image  }}export function removeFavourite (id: string): favouriteActionTypes {  return {    type: REMOVE_FAVOURITE,    id: id  }}

reducers.ts

export function favouriteReducer(  state = initialState,  action: favouriteActionTypes): favouriteState {  switch (action.type) {    case ADD_FAVOURITE:      console.log(`am here in add fav object is: ${action.favourite}`)      return {        favourites: [...state.favourites, action.favourite]      }    case REMOVE_FAVOURITE:      return {        favourites: state.favourites.filter(          favourite => favourite.id !== action.id        )      }    default:      return state  }}

The console.log in the reducer always returns an undefined object.

The component that is calling these actions with buttons is as follows. The this.props.imageThumbnail is a valid object that is being passed into the addFavourite/removeFavourite functions.

component.tsx

const mapState = (state: rootState) => ({  favourites: state.favourites})const mapDispatch = {  addFavourite: (image: ImageThumbnail) => ({ type: 'ADD_FAVOURITE' }),  removeFavourite: (id: string) => ({ type: 'REMOVE_FAVOURITE' })}//component declaration//render method<TouchableOpacity  onPress={() => this.props.addFavourite(this.props.imageThumbnail)}/><TouchableOpacity  onPress={() => this.props.removeFavourite(this.props.imageThumbnail.id)}/>const connector = connect(  mapState,  mapDispatch)type PropsFromRedux = ConnectedProps<typeof connector>export default connector(component)