diff --git a/cli/src/build.ts b/cli/src/build.ts
index 1d512310..51f66f97 100644
--- a/cli/src/build.ts
+++ b/cli/src/build.ts
@@ -383,6 +383,9 @@ export class ExternalObject<T> {
           dts += indentLines(`}`, nest) + '\n'
           break
         case 'enum':
+          if (!nested) {
+            idents.push(def.name)
+          }
           dts +=
             indentLines(`${def.js_doc}export enum ${def.name} {`, nest) + '\n'
           dts += indentLines(def.def, nest + 2) + '\n'
diff --git a/crates/backend/src/codegen/struct.rs b/crates/backend/src/codegen/struct.rs
index dc2efb75..655d6ab5 100644
--- a/crates/backend/src/codegen/struct.rs
+++ b/crates/backend/src/codegen/struct.rs
@@ -239,17 +239,37 @@ impl NapiStruct {
     for field in self.fields.iter() {
       let field_js_name = &field.js_name;
       let ty = &field.ty;
-
+      let is_optional_field = if let syn::Type::Path(syn::TypePath {
+        path: syn::Path { segments, .. },
+        ..
+      }) = &ty
+      {
+        if let Some(last_path) = segments.last() {
+          last_path.ident == "Option"
+        } else {
+          false
+        }
+      } else {
+        false
+      };
       match &field.name {
         syn::Member::Named(ident) => {
           field_destructions.push(quote! { #ident });
           obj_field_setters.push(quote! { obj.set(#field_js_name, #ident)?; });
-          obj_field_getters.push(quote! { let #ident: #ty = obj.get(#field_js_name)?.expect(&format!("Field {} should exist", #field_js_name)); });
+          if is_optional_field {
+            obj_field_getters.push(quote! { let #ident: #ty = obj.get(#field_js_name)?; });
+          } else {
+            obj_field_getters.push(quote! { let #ident: #ty = obj.get(#field_js_name)?.expect(&format!("Field {} should exist", #field_js_name)); });
+          }
         }
         syn::Member::Unnamed(i) => {
           field_destructions.push(quote! { arg#i });
           obj_field_setters.push(quote! { obj.set(#field_js_name, arg#1)?; });
-          obj_field_getters.push(quote! { let arg#i: #ty = obj.get(#field_js_name)?.expect(&format!("Field {} should exist", #field_js_name)); });
+          if is_optional_field {
+            obj_field_getters.push(quote! { let arg#i: #ty = obj.get(#field_js_name)?; });
+          } else {
+            obj_field_getters.push(quote! { let arg#i: #ty = obj.get(#field_js_name)?.expect(&format!("Field {} should exist", #field_js_name)); });
+          }
         }
       }
     }
diff --git a/crates/backend/src/typegen.rs b/crates/backend/src/typegen.rs
index 2b86c926..8076e4b9 100644
--- a/crates/backend/src/typegen.rs
+++ b/crates/backend/src/typegen.rs
@@ -3,7 +3,7 @@ mod r#enum;
 mod r#fn;
 pub(crate) mod r#struct;
 
-use std::collections::HashMap;
+use std::{cell::RefCell, collections::HashMap};
 
 use once_cell::sync::Lazy;
 use syn::Type;
@@ -17,6 +17,16 @@ pub struct TypeDef {
   pub js_doc: String,
 }
 
+thread_local! {
+  static ALIAS: RefCell<HashMap<String, String>> = Default::default();
+}
+
+fn add_alias(name: String, alias: String) {
+  ALIAS.with(|aliases| {
+    aliases.borrow_mut().insert(name, alias);
+  });
+}
+
 pub fn js_doc_from_comments(comments: &[String]) -> String {
   if comments.is_empty() {
     return "".to_owned();
@@ -248,7 +258,13 @@ pub fn ty_to_ts_type(ty: &Type, is_return_ty: bool) -> (String, bool) {
           ));
         } else {
           // there should be runtime registered type in else
-          ts_ty = Some((rust_ty, false));
+          let type_alias = ALIAS.with(|aliases| {
+            aliases
+              .borrow()
+              .get(rust_ty.as_str())
+              .map(|a| (a.to_owned(), false))
+          });
+          ts_ty = type_alias.or(Some((rust_ty, false)));
         }
       }
 
diff --git a/crates/backend/src/typegen/const.rs b/crates/backend/src/typegen/const.rs
index 5ac266be..29343d3a 100644
--- a/crates/backend/src/typegen/const.rs
+++ b/crates/backend/src/typegen/const.rs
@@ -1,9 +1,10 @@
 use super::{ToTypeDef, TypeDef};
 
-use crate::{js_doc_from_comments, ty_to_ts_type, NapiConst};
+use crate::{js_doc_from_comments, ty_to_ts_type, typegen::add_alias, NapiConst};
 
 impl ToTypeDef for NapiConst {
   fn to_type_def(&self) -> TypeDef {
+    add_alias(self.name.to_string(), self.js_name.to_string());
     TypeDef {
       kind: "const".to_owned(),
       name: self.js_name.to_owned(),
diff --git a/crates/backend/src/typegen/enum.rs b/crates/backend/src/typegen/enum.rs
index 3046c648..eeabbe53 100644
--- a/crates/backend/src/typegen/enum.rs
+++ b/crates/backend/src/typegen/enum.rs
@@ -1,8 +1,9 @@
-use super::{ToTypeDef, TypeDef};
+use super::{add_alias, ToTypeDef, TypeDef};
 use crate::{js_doc_from_comments, NapiEnum};
 
 impl ToTypeDef for NapiEnum {
   fn to_type_def(&self) -> TypeDef {
+    add_alias(self.name.to_string(), self.js_name.to_string());
     TypeDef {
       kind: "enum".to_owned(),
       name: self.js_name.to_owned(),
diff --git a/crates/backend/src/typegen/struct.rs b/crates/backend/src/typegen/struct.rs
index d44a8b24..c592bf8b 100644
--- a/crates/backend/src/typegen/struct.rs
+++ b/crates/backend/src/typegen/struct.rs
@@ -1,7 +1,7 @@
 use std::cell::RefCell;
 use std::collections::HashMap;
 
-use super::{ToTypeDef, TypeDef};
+use super::{add_alias, ToTypeDef, TypeDef};
 use crate::{js_doc_from_comments, ty_to_ts_type, NapiImpl, NapiStruct, NapiStructKind};
 
 thread_local! {
@@ -15,6 +15,7 @@ impl ToTypeDef for NapiStruct {
       c.borrow_mut()
         .insert(self.name.to_string(), self.js_name.clone());
     });
+    add_alias(self.name.to_string(), self.js_name.to_string());
     TypeDef {
       kind: String::from(if self.kind == NapiStructKind::Object {
         "interface"
diff --git a/crates/macro/src/parser/attrs.rs b/crates/macro/src/parser/attrs.rs
index a04da0ef..111135d5 100644
--- a/crates/macro/src/parser/attrs.rs
+++ b/crates/macro/src/parser/attrs.rs
@@ -1,9 +1,8 @@
+use std::cell::{Cell, RefCell};
+use std::collections::HashMap;
+
 use napi_derive_backend::{bail_span, BindgenResult, Diagnostic};
 use proc_macro2::{Delimiter, Ident, Span, TokenTree};
-use std::{
-  cell::{Cell, RefCell},
-  collections::HashMap,
-};
 use syn::spanned::Spanned;
 
 thread_local! {
diff --git a/crates/napi/src/bindgen_runtime/js_values/object.rs b/crates/napi/src/bindgen_runtime/js_values/object.rs
index ef0b4d94..04870e59 100644
--- a/crates/napi/src/bindgen_runtime/js_values/object.rs
+++ b/crates/napi/src/bindgen_runtime/js_values/object.rs
@@ -35,7 +35,7 @@ impl Object {
 
       let ty = type_of!(self.0.env, ret)?;
 
-      Ok(if ty == ValueType::Undefined {
+      Ok(if ty == ValueType::Undefined || ty == ValueType::Null {
         None
       } else {
         Some(V::from_napi_value(self.0.env, ret)?)
diff --git a/examples/napi/__test__/typegen.spec.ts.md b/examples/napi/__test__/typegen.spec.ts.md
index a098885d..4b3b4e40 100644
--- a/examples/napi/__test__/typegen.spec.ts.md
+++ b/examples/napi/__test__/typegen.spec.ts.md
@@ -73,6 +73,20 @@ Generated by [AVA](https://avajs.dev).
     export function getGlobal(): typeof global␊
     export function getUndefined(): void␊
     export function getNull(): JsNull␊
+    export interface AllOptionalObject {␊
+      name?: string | undefined | null␊
+      age?: number | undefined | null␊
+    }␊
+    export function receiveAllOptionalObject(obj?: AllOptionalObject | undefined | null): void␊
+    export enum ALIAS {␊
+      A = 0,␊
+      B = 1␊
+    }␊
+    export interface AliasedStruct {␊
+      a: ALIAS␊
+      b: number␊
+    }␊
+    export function fnReceivedAliased(s: AliasedStruct, e: ALIAS): void␊
     export function asyncPlus100(p: Promise<number>): Promise<number>␊
     /** This is an interface for package.json */␊
     export interface PackageJson {␊
diff --git a/examples/napi/__test__/typegen.spec.ts.snap b/examples/napi/__test__/typegen.spec.ts.snap
index f674e93d..b73f0fe8 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/__test__/values.spec.ts b/examples/napi/__test__/values.spec.ts
index 570fbd3c..a66153cb 100644
--- a/examples/napi/__test__/values.spec.ts
+++ b/examples/napi/__test__/values.spec.ts
@@ -59,6 +59,10 @@ import {
   convertU32Array,
   createExternalTypedArray,
   mutateTypedArray,
+  receiveAllOptionalObject,
+  fnReceivedAliased,
+  ALIAS,
+  AliasedStruct,
 } from '../'
 
 test('export const', (t) => {
@@ -202,6 +206,20 @@ test('function ts type override', (t) => {
   t.deepEqual(tsRename({ foo: 1, bar: 2, baz: 2 }), ['foo', 'bar', 'baz'])
 })
 
+test('option object', (t) => {
+  t.notThrows(() => receiveAllOptionalObject())
+  t.notThrows(() => receiveAllOptionalObject({}))
+})
+
+test('aliased rust struct and enum', (t) => {
+  const a: ALIAS = ALIAS.A
+  const b: AliasedStruct = {
+    a,
+    b: 1,
+  }
+  t.notThrows(() => fnReceivedAliased(b, ALIAS.B))
+})
+
 test('serde-json', (t) => {
   const packageJson = readPackageJson()
   t.is(packageJson.name, 'napi-rs')
diff --git a/examples/napi/index.d.ts b/examples/napi/index.d.ts
index f514c30d..3e9dbb64 100644
--- a/examples/napi/index.d.ts
+++ b/examples/napi/index.d.ts
@@ -63,6 +63,20 @@ export function createObj(): object
 export function getGlobal(): typeof global
 export function getUndefined(): void
 export function getNull(): JsNull
+export interface AllOptionalObject {
+  name?: string | undefined | null
+  age?: number | undefined | null
+}
+export function receiveAllOptionalObject(obj?: AllOptionalObject | undefined | null): void
+export enum ALIAS {
+  A = 0,
+  B = 1
+}
+export interface AliasedStruct {
+  a: ALIAS
+  b: number
+}
+export function fnReceivedAliased(s: AliasedStruct, e: ALIAS): void
 export function asyncPlus100(p: Promise<number>): Promise<number>
 /** This is an interface for package.json */
 export interface PackageJson {
diff --git a/examples/napi/src/object.rs b/examples/napi/src/object.rs
index 71c868a1..741c74cf 100644
--- a/examples/napi/src/object.rs
+++ b/examples/napi/src/object.rs
@@ -27,3 +27,35 @@ fn get_undefined(env: Env) -> Result<JsUndefined> {
 fn get_null(env: Env) -> Result<JsNull> {
   env.get_null()
 }
+
+#[napi(object)]
+struct AllOptionalObject {
+  pub name: Option<String>,
+  pub age: Option<u32>,
+}
+
+#[napi]
+fn receive_all_optional_object(obj: Option<AllOptionalObject>) -> Result<()> {
+  if obj.is_some() {
+    assert!(obj.as_ref().unwrap().name.is_none());
+    assert!(obj.as_ref().unwrap().age.is_none());
+  }
+  Ok(())
+}
+
+#[napi(js_name = "ALIAS")]
+pub enum AliasedEnum {
+  A,
+  B,
+}
+
+#[napi(object, js_name = "AliasedStruct")]
+pub struct StructContainsAliasedEnum {
+  pub a: AliasedEnum,
+  pub b: u32,
+}
+
+#[napi]
+fn fn_received_aliased(mut s: StructContainsAliasedEnum, e: AliasedEnum) {
+  s.a = e;
+}