diff --git a/crates/backend/src/typegen.rs b/crates/backend/src/typegen.rs
index 75efceb7..916fbd37 100644
--- a/crates/backend/src/typegen.rs
+++ b/crates/backend/src/typegen.rs
@@ -213,9 +213,9 @@ fn fill_ty(template: &str, args: Vec<String>) -> String {
   ret
 }
 
-pub fn ty_to_ts_type(ty: &Type, is_return_ty: bool) -> (String, bool) {
+pub fn ty_to_ts_type(ty: &Type, is_return_ty: bool, is_struct_field: bool) -> (String, bool) {
   match ty {
-    Type::Reference(r) => ty_to_ts_type(&r.elem, is_return_ty),
+    Type::Reference(r) => ty_to_ts_type(&r.elem, is_return_ty, is_struct_field),
     Type::Tuple(tuple) => {
       if tuple.elems.is_empty() {
         ("undefined".to_owned(), false)
@@ -226,7 +226,7 @@ pub fn ty_to_ts_type(ty: &Type, is_return_ty: bool) -> (String, bool) {
             tuple
               .elems
               .iter()
-              .map(|elem| ty_to_ts_type(elem, false).0)
+              .map(|elem| ty_to_ts_type(elem, false, false).0)
               .collect::<Vec<_>>()
               .join(", ")
           ),
@@ -244,7 +244,9 @@ pub fn ty_to_ts_type(ty: &Type, is_return_ty: bool) -> (String, bool) {
             .args
             .iter()
             .filter_map(|arg| match arg {
-              syn::GenericArgument::Type(generic_ty) => Some(ty_to_ts_type(generic_ty, false)),
+              syn::GenericArgument::Type(generic_ty) => {
+                Some(ty_to_ts_type(generic_ty, false, false))
+              }
               _ => None,
             })
             .collect::<Vec<_>>()
@@ -255,9 +257,18 @@ pub fn ty_to_ts_type(ty: &Type, is_return_ty: bool) -> (String, bool) {
         if rust_ty == "Result" && is_return_ty {
           ts_ty = Some(args.first().unwrap().to_owned());
         } else if rust_ty == "Option" {
-          ts_ty = args
-            .first()
-            .map(|(arg, _)| (format!("{} | undefined | null", arg), true));
+          ts_ty = args.first().map(|(arg, _)| {
+            (
+              if is_struct_field {
+                arg.to_string()
+              } else if is_return_ty {
+                format!("{}?", arg)
+              } else {
+                format!("{} | undefined | null", arg)
+              },
+              true,
+            )
+          });
         } else if rust_ty == "AsyncTask" {
           ts_ty = r#struct::TASK_STRUCTS.with(|t| {
             let (output_type, _) = args.first().unwrap().to_owned();
@@ -299,7 +310,7 @@ pub fn ty_to_ts_type(ty: &Type, is_return_ty: bool) -> (String, bool) {
 
       ts_ty.unwrap_or_else(|| ("any".to_owned(), false))
     }
-    Type::Group(g) => ty_to_ts_type(&g.elem, is_return_ty),
+    Type::Group(g) => ty_to_ts_type(&g.elem, is_return_ty, is_struct_field),
     _ => ("any".to_owned(), false),
   }
 }
diff --git a/crates/backend/src/typegen/const.rs b/crates/backend/src/typegen/const.rs
index 7def2c14..e926608d 100644
--- a/crates/backend/src/typegen/const.rs
+++ b/crates/backend/src/typegen/const.rs
@@ -17,7 +17,7 @@ impl ToTypeDef for NapiConst {
       def: format!(
         "export const {}: {}",
         &self.js_name,
-        ty_to_ts_type(&self.type_name, false).0
+        ty_to_ts_type(&self.type_name, false, false).0
       ),
       js_mod: self.js_mod.to_owned(),
       js_doc: js_doc_from_comments(&self.comments),
diff --git a/crates/backend/src/typegen/fn.rs b/crates/backend/src/typegen/fn.rs
index b1b2133d..91f65407 100644
--- a/crates/backend/src/typegen/fn.rs
+++ b/crates/backend/src/typegen/fn.rs
@@ -97,7 +97,7 @@ fn gen_callback_type(callback: &CallbackArg) -> String {
       .iter()
       .enumerate()
       .map(|(i, arg)| {
-        let (ts_type, is_optional) = ty_to_ts_type(arg, false);
+        let (ts_type, is_optional) = ty_to_ts_type(arg, false, false);
         FnArg {
           arg: format!("arg{}", i),
           ts_type,
@@ -106,7 +106,7 @@ fn gen_callback_type(callback: &CallbackArg) -> String {
       })
       .collect::<FnArgList>(),
     ret = match &callback.ret {
-      Some(ty) => ty_to_ts_type(ty, true).0,
+      Some(ty) => ty_to_ts_type(ty, true, false).0,
       None => "void".to_owned(),
     }
   )
@@ -131,7 +131,7 @@ impl NapiFn {
               i.mutability = None;
             }
             let arg = path.pat.to_token_stream().to_string().to_case(Case::Camel);
-            let (ts_type, is_optional) = ty_to_ts_type(&path.ty, false);
+            let (ts_type, is_optional) = ty_to_ts_type(&path.ty, false, false);
 
             Some(FnArg {
               arg,
@@ -181,7 +181,7 @@ impl NapiFn {
         .unwrap_or_else(|| "".to_owned()),
       _ => {
         let ret = if let Some(ret) = &self.ret {
-          let (ts_type, _) = ty_to_ts_type(ret, true);
+          let (ts_type, _) = ty_to_ts_type(ret, true, false);
           if ts_type == "undefined" {
             "void".to_owned()
           } else if ts_type == "Self" {
diff --git a/crates/backend/src/typegen/struct.rs b/crates/backend/src/typegen/struct.rs
index d09047bc..36968760 100644
--- a/crates/backend/src/typegen/struct.rs
+++ b/crates/backend/src/typegen/struct.rs
@@ -36,8 +36,10 @@ impl ToTypeDef for NapiImpl {
   fn to_type_def(&self) -> Option<TypeDef> {
     if let Some(output_type) = &self.task_output_type {
       TASK_STRUCTS.with(|t| {
-        t.borrow_mut()
-          .insert(self.js_name.clone(), ty_to_ts_type(output_type, false).0);
+        t.borrow_mut().insert(
+          self.js_name.clone(),
+          ty_to_ts_type(output_type, false, true).0,
+        );
       });
     }
 
@@ -90,7 +92,7 @@ impl NapiStruct {
           field_str.push_str("readonly ")
         }
 
-        let (arg, is_optional) = ty_to_ts_type(&f.ty, false);
+        let (arg, is_optional) = ty_to_ts_type(&f.ty, false, true);
         let arg = f.ts_type.as_ref().map(|ty| ty.to_string()).unwrap_or(arg);
 
         let sep = if is_optional { "?" } else { "" };
diff --git a/examples/napi/__test__/typegen.spec.ts.md b/examples/napi/__test__/typegen.spec.ts.md
index 3a8c38e5..beea5282 100644
--- a/examples/napi/__test__/typegen.spec.ts.md
+++ b/examples/napi/__test__/typegen.spec.ts.md
@@ -46,7 +46,7 @@ Generated by [AVA](https://avajs.dev).
     export function chronoDateAdd1Minute(input: Date): Date␊
     export interface Dates {␊
       start: Date␊
-      end?: Date | undefined | null␊
+      end?: Date␊
     }␊
     export function eitherStringOrNumber(input: string | number): number␊
     export function returnEither(input: number): string | number␊
@@ -106,7 +106,7 @@ Generated by [AVA](https://avajs.dev).
     export function xxh64Alias(input: Buffer): bigint␊
     export function getMapping(): Record<string, number>␊
     export function sumMapping(nums: Record<string, number>): number␊
-    export function mapOption(val?: number | undefined | null): number | undefined | null␊
+    export function mapOption(val?: number | undefined | null): number?␊
     export function returnNull(): null␊
     export function returnUndefined(): void␊
     export function add(a: number, b: number): number␊
@@ -117,8 +117,8 @@ Generated by [AVA](https://avajs.dev).
     export function getUndefined(): void␊
     export function getNull(): JsNull␊
     export interface AllOptionalObject {␊
-      name?: string | undefined | null␊
-      age?: number | undefined | null␊
+      name?: string␊
+      age?: number␊
     }␊
     export function receiveAllOptionalObject(obj?: AllOptionalObject | undefined | null): void␊
     export const enum ALIAS {␊
@@ -147,8 +147,8 @@ Generated by [AVA](https://avajs.dev).
       name: string␊
       /** The version of the package */␊
       version: string␊
-      dependencies?: Record<string, any> | undefined | null␊
-      devDependencies?: Record<string, any> | undefined | null␊
+      dependencies?: Record<string, any>␊
+      devDependencies?: Record<string, any>␊
     }␊
     export function readPackageJson(): PackageJson␊
     export function getPackageJsonName(packageJson: PackageJson): string␊
@@ -221,7 +221,7 @@ Generated by [AVA](https://avajs.dev).
     export type Blake2bKey = Blake2BKey␊
     export class Blake2BKey { }␊
     export class Context {␊
-      maybeNeed?: boolean | undefined | null␊
+      maybeNeed?: boolean␊
       constructor()␊
       static withData(data: string): Context␊
       method(): string␊
@@ -241,7 +241,7 @@ Generated by [AVA](https://avajs.dev).
     export type JsAssets = Assets␊
     export class Assets {␊
       constructor()␊
-      get(id: number): JsAsset | undefined | null␊
+      get(id: number): JsAsset?␊
     }␊
     export type JsAsset = Asset␊
     export class Asset {␊
diff --git a/examples/napi/__test__/typegen.spec.ts.snap b/examples/napi/__test__/typegen.spec.ts.snap
index 68e1450c..0274c678 100644
Binary files a/examples/napi/__test__/typegen.spec.ts.snap and b/examples/napi/__test__/typegen.spec.ts.snap differ
diff --git a/examples/napi/index.d.ts b/examples/napi/index.d.ts
index c03e1ff1..ceab0ab7 100644
--- a/examples/napi/index.d.ts
+++ b/examples/napi/index.d.ts
@@ -36,7 +36,7 @@ export function chronoDateToMillis(input: Date): number
 export function chronoDateAdd1Minute(input: Date): Date
 export interface Dates {
   start: Date
-  end?: Date | undefined | null
+  end?: Date
 }
 export function eitherStringOrNumber(input: string | number): number
 export function returnEither(input: number): string | number
@@ -96,7 +96,7 @@ export function tsRename(a: { foo: number }): string[]
 export function xxh64Alias(input: Buffer): bigint
 export function getMapping(): Record<string, number>
 export function sumMapping(nums: Record<string, number>): number
-export function mapOption(val?: number | undefined | null): number | undefined | null
+export function mapOption(val?: number | undefined | null): number?
 export function returnNull(): null
 export function returnUndefined(): void
 export function add(a: number, b: number): number
@@ -107,8 +107,8 @@ export function getGlobal(): typeof global
 export function getUndefined(): void
 export function getNull(): JsNull
 export interface AllOptionalObject {
-  name?: string | undefined | null
-  age?: number | undefined | null
+  name?: string
+  age?: number
 }
 export function receiveAllOptionalObject(obj?: AllOptionalObject | undefined | null): void
 export const enum ALIAS {
@@ -137,8 +137,8 @@ export interface PackageJson {
   name: string
   /** The version of the package */
   version: string
-  dependencies?: Record<string, any> | undefined | null
-  devDependencies?: Record<string, any> | undefined | null
+  dependencies?: Record<string, any>
+  devDependencies?: Record<string, any>
 }
 export function readPackageJson(): PackageJson
 export function getPackageJsonName(packageJson: PackageJson): string
@@ -211,7 +211,7 @@ export class Blake2BHasher {
 export type Blake2bKey = Blake2BKey
 export class Blake2BKey { }
 export class Context {
-  maybeNeed?: boolean | undefined | null
+  maybeNeed?: boolean
   constructor()
   static withData(data: string): Context
   method(): string
@@ -231,7 +231,7 @@ export class NinjaTurtle {
 export type JsAssets = Assets
 export class Assets {
   constructor()
-  get(id: number): JsAsset | undefined | null
+  get(id: number): JsAsset?
 }
 export type JsAsset = Asset
 export class Asset {