diff --git a/src/CodeGeneration/TypeScript.hs b/src/CodeGeneration/TypeScript.hs
index d9cf7b8..5c58f67 100644
--- a/src/CodeGeneration/TypeScript.hs
+++ b/src/CodeGeneration/TypeScript.hs
@@ -28,7 +28,8 @@ outputModule module' =
           if Text.null importsOutput then "" else importsOutput <> "\n\n",
           declarationImportOutput,
           if null declarationNames then "" else "\n\n",
-          definitionOutput
+          definitionOutput,
+          "\n"
         ]
 
 modulePrelude :: Text
@@ -1088,6 +1089,8 @@ unionEnumConstructorTag unionName constructorName' =
   mconcat [unionName, "Tag.", upperCaseFirst constructorName']
 
 outputField :: StructField -> Text
+outputField (StructField (FieldName name) (ComplexType (OptionalType fieldType))) =
+  mconcat ["    ", name, "?: ", outputFieldType fieldType, ";\n"]
 outputField (StructField (FieldName name) fieldType) =
   mconcat ["    ", name, ": ", outputFieldType fieldType, ";\n"]
 
diff --git a/test/reference-output/arrayOfArraysOfNullableStrings.ts b/test/reference-output/arrayOfArraysOfNullableStrings.ts
index a2c521c..e79d35c 100644
--- a/test/reference-output/arrayOfArraysOfNullableStrings.ts
+++ b/test/reference-output/arrayOfArraysOfNullableStrings.ts
@@ -10,4 +10,4 @@ export function isType(value: unknown): value is Type {
 
 export function validateType(value: unknown): svt.ValidationResult<Type> {
     return svt.validate<Type>(value, {field: svt.validateArray(svt.validateArray(svt.validateOptional(svt.validateString)))});
-}
\ No newline at end of file
+}
diff --git a/test/reference-output/basic.ts b/test/reference-output/basic.ts
index 26cc0c8..4bb810c 100644
--- a/test/reference-output/basic.ts
+++ b/test/reference-output/basic.ts
@@ -4,7 +4,7 @@ export type Recruiter = {
     type: "Recruiter";
     Name: string;
     emails: (string | null | undefined)[];
-    recruiter: Recruiter | null | undefined;
+    recruiter?: Recruiter;
     created: bigint;
 };
 
@@ -429,4 +429,4 @@ export function validateEmbeddedLogIn(value: unknown): svt.ValidationResult<Embe
 
 export function validateSystemImploded(value: unknown): svt.ValidationResult<SystemImploded> {
     return svt.validate<SystemImploded>(value, {type: EmbeddedEventTag.SystemImploded});
-}
\ No newline at end of file
+}
diff --git a/test/reference-output/generics.ts b/test/reference-output/generics.ts
index 582ac71..b11f31e 100644
--- a/test/reference-output/generics.ts
+++ b/test/reference-output/generics.ts
@@ -34,11 +34,11 @@ export function validateUsingOwnGenerics<T>(validateT: svt.Validator<T>): svt.Va
 
 export type KnownForMovie = {
     media_type: "movie";
-    poster_path: string | null | undefined;
+    poster_path?: string;
     id: number;
-    title: string | null | undefined;
+    title?: string;
     vote_average: number;
-    release_date: string | null | undefined;
+    release_date?: string;
     overview: string;
 };
 
@@ -52,12 +52,12 @@ export function validateKnownForMovie(value: unknown): svt.ValidationResult<Know
 
 export type KnownForShow = {
     media_type: "tv";
-    poster_path: string | null | undefined;
+    poster_path?: string;
     id: number;
     vote_average: number;
     overview: string;
-    first_air_date: string | null | undefined;
-    name: string | null | undefined;
+    first_air_date?: string;
+    name?: string;
 };
 
 export function isKnownForShow(value: unknown): value is KnownForShow {
@@ -79,11 +79,11 @@ export function validateKnownFor(value: unknown): svt.ValidationResult<KnownFor>
 }
 
 export type KnownForMovieWithoutTypeTag = {
-    poster_path: string | null | undefined;
+    poster_path?: string;
     id: number;
-    title: string | null | undefined;
+    title?: string;
     vote_average: number;
-    release_date: string | null | undefined;
+    release_date?: string;
     overview: string;
 };
 
@@ -96,12 +96,12 @@ export function validateKnownForMovieWithoutTypeTag(value: unknown): svt.Validat
 }
 
 export type KnownForShowWithoutTypeTag = {
-    poster_path: string | null | undefined;
+    poster_path?: string;
     id: number;
     vote_average: number;
     overview: string;
-    first_air_date: string | null | undefined;
-    name: string | null | undefined;
+    first_air_date?: string;
+    name?: string;
 };
 
 export function isKnownForShowWithoutTypeTag(value: unknown): value is KnownForShowWithoutTypeTag {
@@ -121,22 +121,22 @@ export enum KnownForEmbeddedTag {
 
 export type MovieStartingWithLowercase = {
     media_type: KnownForEmbeddedTag.MovieStartingWithLowercase;
-    poster_path: string | null | undefined;
+    poster_path?: string;
     id: number;
-    title: string | null | undefined;
+    title?: string;
     vote_average: number;
-    release_date: string | null | undefined;
+    release_date?: string;
     overview: string;
 };
 
 export type TvStartingWithLowercase = {
     media_type: KnownForEmbeddedTag.TvStartingWithLowercase;
-    poster_path: string | null | undefined;
+    poster_path?: string;
     id: number;
     vote_average: number;
     overview: string;
-    first_air_date: string | null | undefined;
-    name: string | null | undefined;
+    first_air_date?: string;
+    name?: string;
 };
 
 export function MovieStartingWithLowercase(data: KnownForMovieWithoutTypeTag): MovieStartingWithLowercase {
@@ -180,22 +180,22 @@ export enum KnownForEmbeddedWithUpperCaseTag {
 
 export type Movie = {
     media_type: KnownForEmbeddedWithUpperCaseTag.Movie;
-    poster_path: string | null | undefined;
+    poster_path?: string;
     id: number;
-    title: string | null | undefined;
+    title?: string;
     vote_average: number;
-    release_date: string | null | undefined;
+    release_date?: string;
     overview: string;
 };
 
 export type Tv = {
     media_type: KnownForEmbeddedWithUpperCaseTag.Tv;
-    poster_path: string | null | undefined;
+    poster_path?: string;
     id: number;
     vote_average: number;
     overview: string;
-    first_air_date: string | null | undefined;
-    name: string | null | undefined;
+    first_air_date?: string;
+    name?: string;
 };
 
 export function Movie(data: KnownForMovieWithoutTypeTag): Movie {
@@ -228,4 +228,4 @@ export function validateMovie(value: unknown): svt.ValidationResult<Movie> {
 
 export function validateTv(value: unknown): svt.ValidationResult<Tv> {
     return svt.validate<Tv>(value, {media_type: KnownForEmbeddedWithUpperCaseTag.Tv, poster_path: svt.validateOptional(svt.validateString), id: svt.validateNumber, vote_average: svt.validateNumber, overview: svt.validateString, first_air_date: svt.validateOptional(svt.validateString), name: svt.validateOptional(svt.validateString)});
-}
\ No newline at end of file
+}
diff --git a/test/reference-output/github.ts b/test/reference-output/github.ts
index 426a575..6abb065 100644
--- a/test/reference-output/github.ts
+++ b/test/reference-output/github.ts
@@ -16,8 +16,8 @@ export type UserData = {
     following: number;
     created_at: string;
     updated_at: string;
-    location: string | null | undefined;
-    blog: string | null | undefined;
+    location?: string;
+    blog?: string;
 };
 
 export function isUserData(value: unknown): value is UserData {
@@ -51,9 +51,9 @@ export type OrganizationData = {
     login: string;
     id: number;
     avatar_url: string;
-    members_url: string | null | undefined;
+    members_url?: string;
     repos_url: string;
-    description: string | null | undefined;
+    description?: string;
 };
 
 export function isOrganizationData(value: unknown): value is OrganizationData {
@@ -88,9 +88,9 @@ export type Organization = {
     login: string;
     id: number;
     avatar_url: string;
-    members_url: string | null | undefined;
+    members_url?: string;
     repos_url: string;
-    description: string | null | undefined;
+    description?: string;
 };
 
 export function User(data: OwnerData): User {
@@ -133,11 +133,11 @@ export type Repository = {
     fork: boolean;
     created_at: string;
     updated_at: string;
-    description: string | null | undefined;
+    description?: string;
     owner: Owner;
     url: string;
     html_url: string;
-    language: string | null | undefined;
+    language?: string;
 };
 
 export function isRepository(value: unknown): value is Repository {
@@ -203,12 +203,12 @@ export type Issue = {
     labels: Label[];
     state: string;
     locked: boolean;
-    assignee: UserData | null | undefined;
+    assignee?: UserData;
     assignees: UserData[];
     comments: number;
     created_at: string;
     updated_at: string;
-    closed_at: string | null | undefined;
+    closed_at?: string;
     author_association: string;
     body: string;
 };
@@ -310,4 +310,4 @@ export function isRepositorySearchData(value: unknown): value is RepositorySearc
 
 export function validateRepositorySearchData(value: unknown): svt.ValidationResult<RepositorySearchData> {
     return svt.validate<RepositorySearchData>(value, {total_count: svt.validateNumber, incomplete_results: svt.validateBoolean, items: svt.validateArray(validateRepository)});
-}
\ No newline at end of file
+}
diff --git a/test/reference-output/hasGeneric.ts b/test/reference-output/hasGeneric.ts
index 2e5b3e3..b3c9cb8 100644
--- a/test/reference-output/hasGeneric.ts
+++ b/test/reference-output/hasGeneric.ts
@@ -152,4 +152,4 @@ export function validateGenericEvent<T>(validateT: svt.Validator<T>): svt.Valida
     return function validateGenericEventT(value: unknown): svt.ValidationResult<GenericEvent<T>> {
         return svt.validate<GenericEvent<T>>(value, {type: HasGenericEventTag.GenericEvent, data: external.validateOption(validateT)});
     };
-}
\ No newline at end of file
+}
diff --git a/test/reference-output/importExample.ts b/test/reference-output/importExample.ts
index a64550b..7c10d4d 100644
--- a/test/reference-output/importExample.ts
+++ b/test/reference-output/importExample.ts
@@ -102,4 +102,4 @@ export function isAllConcrete(value: unknown): value is AllConcrete {
 
 export function validateAllConcrete(value: unknown): svt.ValidationResult<AllConcrete> {
     return svt.validate<AllConcrete>(value, {field: validateHoldsSomething(basic.validateEither(basic.validateMaybe(validateStructureUsingImport), validateUnionUsingImport))});
-}
\ No newline at end of file
+}