use types instead of interfaces

db/booking.ts

@@ -7,25 +7,24 @@ import { Booker } from './booker'
 import { BOOKING_STATUS, VALIDATION_ERRORS } from './enums'
 import { getBookedDays } from './index'
 
-export interface Booking {
+export type Booking = {
   uuid: string
-  booker: Booker
-  bill: Bill
+  booker?: Booker
+  bill?: Bill
   startDate: string
   endDate: string
-  status: BOOKING_STATUS
+  status?: BOOKING_STATUS
   purpose?: string
   org?: string
   destination?: string
   days?: string[]
 }
 
-export interface BookingDocument
-  extends Booking,
-  mongoose.Document,
-  mongoose.SchemaTimestampsConfig { }
+export type BookingDocument = Booking &
+  mongoose.Document &
+  mongoose.SchemaTimestampsConfig
 
-export interface BookingModel extends mongoose.Model<BookingDocument> {
+export type BookingModel = mongoose.Model<BookingDocument> & {
   findBookedDays(uuidsToIngore?: string[]): Promise<string[]>
 }
 
@@ -52,10 +51,11 @@ const BookingSchema = new mongoose.Schema<BookingDocument>(
       required: true,
       get: dateFormatBackend,
       validate: {
-        validator: function(v: Date): boolean {
+        validator: function (v: Date): boolean {
           return v >= nowInTz()
         },
-        message: (props: { value: Date }): string => `${props.value} is in the past`,
+        message: (props: { value: Date }): string =>
+          `${props.value} is in the past`,
       },
     },
     endDate: {
@@ -63,17 +63,18 @@ const BookingSchema = new mongoose.Schema<BookingDocument>(
       required: false,
       get: dateFormatBackend,
       validate: {
-        validator: function(v: Date): boolean {
+        validator: function (v: Date): boolean {
           return v >= nowInTz()
         },
-        message: (props: { value: Date }): string => `${props.value} is in the past`,
+        message: (props: { value: Date }): string =>
+          `${props.value} is in the past`,
       },
     },
     days: {
       type: [String],
       required: true,
       validate: {
-        validator: async function(days: string[]): Promise<boolean> {
+        validator: async function (days: string[]): Promise<boolean> {
           const booking = this as Booking
           const uuid = booking.uuid && [booking.uuid]
           const bookedDays = await getBookedDays(uuid)
@@ -105,7 +106,7 @@ const BookingSchema = new mongoose.Schema<BookingDocument>(
   }
 )
 
-BookingSchema.pre('validate', function(next: () => void): void {
+BookingSchema.pre('validate', function (next: () => void): void {
   const booking = this as BookingDocument
   booking.days = getDays({
     startDate: new Date(booking.startDate),
@@ -114,7 +115,7 @@ BookingSchema.pre('validate', function(next: () => void): void {
   next()
 })
 
-BookingSchema.static('findBookedDays', async function(
+BookingSchema.static('findBookedDays', async function (
   uuidsToIngore: string[] = []
 ): Promise<string[]> {
   const model = this as BookingModel