fix(napi-derive-backend): Option value should produce optional types

crates/backend/src/typegen.rs

@@ -69,7 +69,6 @@ static KNOWN_TYPES: Lazy<HashMap<&'static str, &'static str>> = Lazy::new(|| {
     ("Buffer", "Buffer"),
     // TODO: Vec<u8> should be Buffer, now is Array<number>
     ("Vec", "Array<{}>"),
-    ("Option", "{} | null"),
     ("Result", "Error | {}"),
     ("Either", "{} | {}"),
     ("Either3", "{} | {} | {}"),
@@ -106,21 +105,24 @@ fn fill_ty(template: &str, args: Vec<String>) -> String {
   ret
 }
 
-pub fn ty_to_ts_type(ty: &Type, is_return_ty: bool) -> String {
+pub fn ty_to_ts_type(ty: &Type, is_return_ty: bool) -> (String, bool) {
   match ty {
     Type::Reference(r) => ty_to_ts_type(&r.elem, is_return_ty),
     Type::Tuple(tuple) => {
       if tuple.elems.is_empty() {
-        "undefined".to_owned()
+        ("undefined".to_owned(), false)
       } else {
+        (
           format!(
             "[{}]",
             tuple
               .elems
               .iter()
-            .map(|elem| ty_to_ts_type(elem, false))
+              .map(|elem| ty_to_ts_type(elem, false).0)
               .collect::<Vec<_>>()
               .join(", ")
+          ),
+          false,
         )
       }
     }
@@ -144,36 +146,46 @@ pub fn ty_to_ts_type(ty: &Type, is_return_ty: bool) -> String {
 
         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));
         } else if rust_ty == "AsyncTask" {
           ts_ty = r#struct::TASK_STRUCTS.with(|t| {
-            let output_type = args.first().unwrap().to_owned();
+            let (output_type, _) = args.first().unwrap().to_owned();
             if let Some(o) = t.borrow().get(&output_type) {
-              Some(format!("Promise<{}>", o))
+              Some((format!("Promise<{}>", o), false))
             } else {
-              Some("Promise<unknown>".to_owned())
+              Some(("Promise<unknown>".to_owned(), false))
             }
           });
         } else if let Some(&known_ty) = KNOWN_TYPES.get(rust_ty.as_str()) {
           if known_ty.contains("{}") {
-            ts_ty = Some(fill_ty(known_ty, args));
+            ts_ty = Some((
+              fill_ty(known_ty, args.into_iter().map(|(arg, _)| arg).collect()),
+              false,
+            ));
           } else {
-            ts_ty = Some(known_ty.to_owned());
+            ts_ty = Some((known_ty.to_owned(), false));
           }
         } else if let Some(t) = crate::typegen::r#struct::CLASS_STRUCTS
           .with(|c| c.borrow_mut().get(rust_ty.as_str()).cloned())
         {
-          ts_ty = Some(t);
+          ts_ty = Some((t, false));
         } else if rust_ty == "Promise" {
-          ts_ty = Some(format!("Promise<{}>", args.first().unwrap()));
+          ts_ty = Some((
+            format!("Promise<{}>", args.first().map(|(arg, _)| arg).unwrap()),
+            false,
+          ));
         } else {
           // there should be runtime registered type in else
-          ts_ty = Some(rust_ty);
+          ts_ty = Some((rust_ty, false));
         }
       }
 
-      ts_ty.unwrap_or_else(|| "any".to_owned())
+      ts_ty.unwrap_or_else(|| ("any".to_owned(), false))
     }
     Type::Group(g) => ty_to_ts_type(&g.elem, is_return_ty),
-    _ => "any".to_owned(),
+    _ => ("any".to_owned(), false),
   }
 }

crates/backend/src/typegen/fn.rs

@@ -30,11 +30,18 @@ fn gen_callback_type(callback: &CallbackArg) -> String {
       .args
       .iter()
       .enumerate()
-      .map(|(i, arg)| { format!("arg{}: {}", i, ty_to_ts_type(arg, false)) })
+      .map(|(i, arg)| {
+        let (arg, is_optional) = ty_to_ts_type(arg, false);
+        if is_optional {
+          format!("arg{}?: {}", i, arg)
+        } else {
+          format!("arg{}: {}", i, arg)
+        }
+      })
       .collect::<Vec<_>>()
       .join(", "),
     ret = match &callback.ret {
-      Some(ty) => ty_to_ts_type(ty, true),
+      Some(ty) => ty_to_ts_type(ty, true).0,
       None => "void".to_owned(),
     }
   )
@@ -56,8 +63,9 @@ impl NapiFn {
             i.mutability = None;
           }
           let mut arg = path.pat.to_token_stream().to_string().to_case(Case::Camel);
-          arg.push_str(": ");
-          arg.push_str(&ty_to_ts_type(&path.ty, false));
+          let (ts_arg, is_optional) = ty_to_ts_type(&path.ty, false);
+          arg.push_str(if is_optional { "?: " } else { ": " });
+          arg.push_str(&ts_arg);
 
           Some(arg)
         }
@@ -100,7 +108,7 @@ 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);
           if ts_type == "undefined" {
             "void".to_owned()
           } else {

crates/backend/src/typegen/struct.rs

@@ -32,7 +32,7 @@ impl ToTypeDef for NapiImpl {
     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));
+          .insert(self.js_name.clone(), ty_to_ts_type(output_type, false).0);
       });
     }
     TypeDef {
@@ -61,7 +61,9 @@ impl NapiStruct {
         if !f.setter {
           field_str.push_str("readonly ")
         }
-        let arg = format!("{}: {}", &f.js_name, ty_to_ts_type(&f.ty, false));
+        let (arg, is_optional) = ty_to_ts_type(&f.ty, false);
+        let sep = if is_optional { "?" } else { "" };
+        let arg = format!("{}{}: {}", &f.js_name, sep, arg);
         if self.kind == NapiStructKind::Constructor {
           ctor_args.push(arg.clone());
         }

examples/napi/index.d.ts

@@ -7,7 +7,7 @@ export function bigintAdd(a: BigInt, b: BigInt): BigInt
 export function createBigInt(): BigInt
 export function createBigIntI64(): BigInt
 export function getCwd(callback: (arg0: string) => void): void
-export function readFile(callback: (arg0: Error | undefined, arg1: string | null) => void): void
+export function readFile(callback: (arg0: Error | undefined, arg1?: string | undefined | null) => void): void
 export function eitherStringOrNumber(input: string | number): number
 export function returnEither(input: number): string | number
 export function either3(input: string | number | boolean): number
@@ -19,7 +19,7 @@ export enum Kind { Dog = 0, Cat = 1, Duck = 2 }
 export enum CustomNumEnum { One = 1, Two = 2, Three = 3, Four = 4, Six = 6, Eight = 8, Nine = 9, Ten = 10 }
 export function enumToI32(e: CustomNumEnum): number
 export function throwError(): void
-export function mapOption(val: number | null): number | null
+export function mapOption(val?: number | undefined | null): number | undefined | null
 export function add(a: number, b: number): number
 export function fibonacci(n: number): number
 export function listObjKeys(obj: object): Array<string>
@@ -31,8 +31,8 @@ export function asyncPlus100(p: Promise<number>): Promise<number>
 interface PackageJson {
   name: string
   version: string
-  dependencies: Record<string, any> | null
-  devDependencies: Record<string, any> | null
+  dependencies?: Record<string, any> | undefined | null
+  devDependencies?: Record<string, any> | undefined | null
 }
 export function readPackageJson(): PackageJson
 export function getPackageJsonName(packageJson: PackageJson): string
@@ -64,7 +64,7 @@ export class Blake2BKey {
   
 }
 export class Context {
-  
+  maybeNeed?: boolean | undefined | null
   constructor()
   static withData(data: string): Context
   method(): string

examples/napi/src/class.rs

@@ -79,6 +79,7 @@ impl Blake2bKey {
 #[napi]
 pub struct Context {
   data: String,
+  pub maybe_need: Option<bool>,
 }
 
 // Test for return `napi::Result` and `Result`
@@ -88,12 +89,16 @@ impl Context {
   pub fn new() -> napi::Result<Self> {
     Ok(Self {
       data: "not empty".into(),
+      maybe_need: None,
     })
   }
 
   #[napi(factory)]
   pub fn with_data(data: String) -> Result<Self> {
-    Ok(Self { data })
+    Ok(Self {
+      data,
+      maybe_need: Some(true),
+    })
   }
 
   #[napi]