use types instead of interfaces

context/book.tsx

@@ -3,27 +3,15 @@ import { useRouter } from 'next/router'
 import { clearBookingData, loadBookingData } from '../helpers/storage'
 
 import { createBooking } from '../helpers/booking'
+import { Booker } from '../db/booker'
+import { Booking } from '../db/booking'
 
-interface BookFormData {
-  startDate: string
-  endDate: string
-  purpose: string
-  org: string
-  destination: string
-  name: string
-  email: string
-  phone: string
-  street: string
-  zip: string
-  city: string
-  storeData?: boolean
-}
+export type BookFormData = Omit<Booking, 'uuid'> &
+  Booker & {
+    storeData?: boolean
+  }
 
-interface Booking {
-  uuid: string
-}
-
-interface BookingStoreState {
+type BookingProviderState = {
   postData?: boolean
   postDataError?: string
   postDataSuccess?: boolean
@@ -34,8 +22,8 @@ interface BookingStoreState {
   dataStoredLoaded: boolean
 }
 
-interface BookStore {
-  state: BookingStoreState
+type BookProvider = {
+  state: BookingProviderState
   dispatch: React.Dispatch<BookAction>
   onChange: (data: object) => void
   onChangeEvent: (event: React.ChangeEvent<React.ElementRef<'input'>>) => void
@@ -43,13 +31,13 @@ interface BookStore {
   forgetData: () => void
 }
 
-interface BookAction {
+type BookAction = {
   type: string
   payload?: any
 }
 
-export const BookContext: React.Context<BookStore> = React.createContext<
-  BookStore
+export const BookContext: React.Context<BookProvider> = React.createContext<
+  BookProvider
 >(null)
 
 export const ACTIONS = {
@@ -61,7 +49,7 @@ export const ACTIONS = {
   DATA_STORED_FORGOTTEN: 'dataStoredForgotten',
 }
 
-function reducer(state: BookingStoreState, action: BookAction) {
+function reducer(state: BookingProviderState, action: BookAction) {
   switch (action.type) {
     case ACTIONS.SET_FORM_DATA:
       return {
@@ -115,7 +103,7 @@ function reducer(state: BookingStoreState, action: BookAction) {
   }
 }
 
-const initialState: BookingStoreState = {
+const initialState: BookingProviderState = {
   postData: false,
   postDataError: null,
   postDataSuccess: null,