feat!(napi): create function from #[napi] fn (#2757)

crates/backend/src/ast.rs

@@ -32,6 +32,7 @@ pub struct NapiFn {
   pub catch_unwind: bool,
   pub unsafe_: bool,
   pub register_name: Ident,
+  pub no_export: bool,
 }
 
 #[derive(Debug, Clone)]

crates/backend/src/codegen.rs

@@ -27,7 +27,7 @@ pub trait TryToTokens {
 }
 
 fn get_intermediate_ident(name: &str) -> Ident {
-  let new_name = format!("_napi_internal_register_{name}");
+  let new_name = format!("{name}_c_callback");
   Ident::new(&new_name, Span::call_site())
 }
 

crates/backend/src/codegen/fn.rs

@@ -726,10 +726,14 @@ impl NapiFn {
       let module_register_name = &self.register_name;
       let intermediate_ident = get_intermediate_ident(&name_str);
       let js_mod_ident = js_mod_to_token_stream(self.js_mod.as_ref());
-      let cb_name = Ident::new(&format!("{name_str}_js_function"), Span::call_site());
+      let cb_name = Ident::new(
+        &format!("_napi_rs_internal_register_{name_str}"),
+        Span::call_site(),
+      );
 
       if self.module_exports {
         return quote! {
+          #[doc(hidden)]
           #[allow(non_snake_case)]
           #[allow(clippy::all)]
           unsafe fn #cb_name(env: napi::bindgen_prelude::sys::napi_env, exports: napi::bindgen_prelude::sys::napi_value) -> napi::bindgen_prelude::Result<napi::bindgen_prelude::sys::napi_value> {
@@ -737,6 +741,7 @@ impl NapiFn {
             Ok(exports)
           }
 
+          #[doc(hidden)]
           #[allow(clippy::all)]
           #[allow(non_snake_case)]
           #[cfg(all(not(test), not(target_family = "wasm")))]
@@ -755,7 +760,32 @@ impl NapiFn {
         };
       }
 
+      let register_module_export_tokens = if self.no_export {
+        quote! {}
+      } else {
+        quote! {
+          #[doc(hidden)]
+          #[allow(clippy::all)]
+          #[allow(non_snake_case)]
+          #[cfg(all(not(test), not(target_family = "wasm")))]
+          #[napi::ctor::ctor(crate_path=::napi::ctor)]
+          fn #module_register_name() {
+            napi::bindgen_prelude::register_module_export(#js_mod_ident, #js_name, #cb_name);
+          }
+
+          #[doc(hidden)]
+          #[allow(clippy::all)]
+          #[allow(non_snake_case)]
+          #[cfg(all(not(test), target_family = "wasm"))]
+          #[no_mangle]
+          extern "C" fn #module_register_name() {
+            napi::bindgen_prelude::register_module_export(#js_mod_ident, #js_name, #cb_name);
+          }
+        }
+      };
+
       quote! {
+        #[doc(hidden)]
         #[allow(non_snake_case)]
         #[allow(clippy::all)]
         unsafe fn #cb_name(env: napi::bindgen_prelude::sys::napi_env) -> napi::bindgen_prelude::Result<napi::bindgen_prelude::sys::napi_value> {
@@ -773,25 +803,10 @@ impl NapiFn {
             "Failed to register function `{}`",
             #name_str,
           )?;
-          napi::bindgen_prelude::register_js_function(#js_name, #cb_name, Some(#intermediate_ident));
           Ok(fn_ptr)
         }
 
-        #[allow(clippy::all)]
-        #[allow(non_snake_case)]
-        #[cfg(all(not(test), not(target_family = "wasm")))]
-        #[napi::ctor::ctor(crate_path=::napi::ctor)]
-        fn #module_register_name() {
-          napi::bindgen_prelude::register_module_export(#js_mod_ident, #js_name, #cb_name);
-        }
-
-        #[allow(clippy::all)]
-        #[allow(non_snake_case)]
-        #[cfg(all(not(test), target_family = "wasm"))]
-        #[no_mangle]
-        extern "C" fn #module_register_name() {
-          napi::bindgen_prelude::register_module_export(#js_mod_ident, #js_name, #cb_name);
-        }
+        #register_module_export_tokens
       }
     }
   }

crates/backend/src/typegen.rs

@@ -487,7 +487,7 @@ pub fn ty_to_ts_type(
                 Some((fill_ty(known_ty, union_args), false))
               }
             } else {
-              let filtered_args =
+              let mut filtered_args =
                 if let Some(arg_indices) = KNOWN_TYPES_IGNORE_ARG.get(rust_ty.as_str()) {
                   args
                     .enumerate()
@@ -497,6 +497,9 @@ pub fn ty_to_ts_type(
                 } else {
                   args.collect::<Vec<_>>()
                 };
+              if rust_ty.starts_with("Function") && filtered_args.is_empty() {
+                filtered_args = vec!["arg?: unknown".to_owned(), "unknown".to_owned()];
+              }
 
               Some((fill_ty(known_ty, filtered_args), false))
             }

crates/backend/src/typegen/fn.rs

@@ -67,7 +67,7 @@ impl FromIterator<FnArg> for FnArgList {
 
 impl ToTypeDef for NapiFn {
   fn to_type_def(&self) -> Option<TypeDef> {
-    if self.skip_typescript || self.module_exports {
+    if self.skip_typescript || self.module_exports || self.no_export {
       return None;
     }
 

crates/macro/src/parser/attrs.rs

@@ -80,6 +80,7 @@ macro_rules! attrgen {
       (discriminant, Discriminant(Span, String, Span)),
       (transparent, Transparent(Span)),
       (array, Array(Span)),
+      (no_export, NoExport(Span)),
 
       // impl later
       // (inspectable, Inspectable(Span)),

crates/macro/src/parser/mod.rs

@@ -728,6 +728,13 @@ fn napi_fn_from_decl(
         bail_span!(sig.ident, "module_exports fn can't have generic parameters");
       }
 
+      if opts.no_export().is_some() {
+        bail_span!(
+          sig.ident,
+          "#[napi(no_export)] can not be used with module_exports attribute"
+        );
+      }
+
       for arg in args.iter() {
         match &arg.kind {
           NapiFnArgKind::Callback(_) => {
@@ -897,6 +904,7 @@ fn napi_fn_from_decl(
       catch_unwind: opts.catch_unwind().is_some(),
       unsafe_: sig.unsafety.is_some(),
       register_name: get_register_ident(ident.to_string().as_str()),
+      no_export: opts.no_export().is_some(),
     })
   })
 }
@@ -964,6 +972,12 @@ impl ParseNapi for syn::ItemStruct {
         "#[napi(catch_unwind)] can only be applied to a function or method."
       );
     }
+    if opts.no_export().is_some() {
+      bail_span!(
+        self,
+        "#[napi(no_export)] can only be applied to a function."
+      );
+    }
     if opts.object().is_some() && opts.custom_finalize().is_some() {
       bail_span!(self, "Custom finalize is not supported for #[napi(object)]");
     }
@@ -999,6 +1013,12 @@ impl ParseNapi for syn::ItemImpl {
         "#[napi(catch_unwind)] can only be applied to a function or method."
       );
     }
+    if opts.no_export().is_some() {
+      bail_span!(
+        self,
+        "#[napi(no_export)] can only be applied to a function."
+      );
+    }
     // #[napi] macro will be remove from impl items after converted to ast
     let napi = self.convert_to_ast(opts);
     self.to_tokens(tokens);
@@ -1031,6 +1051,12 @@ impl ParseNapi for syn::ItemEnum {
         "#[napi(catch_unwind)] can only be applied to a function or method."
       );
     }
+    if opts.no_export().is_some() {
+      bail_span!(
+        self,
+        "#[napi(no_export)] can only be applied to a function."
+      );
+    }
     let napi = self.convert_to_ast(opts);
     self.to_tokens(tokens);
 
@@ -1061,6 +1087,12 @@ impl ParseNapi for syn::ItemConst {
         "#[napi(catch_unwind)] can only be applied to a function or method."
       );
     }
+    if opts.no_export().is_some() {
+      bail_span!(
+        self,
+        "#[napi(no_export)] can only be applied to a function."
+      );
+    }
     let napi = self.convert_to_ast(opts);
     self.to_tokens(tokens);
     napi
@@ -1090,6 +1122,12 @@ impl ParseNapi for syn::ItemType {
         "#[napi(catch_unwind)] can only be applied to a function or method."
       );
     }
+    if opts.no_export().is_some() {
+      bail_span!(
+        self,
+        "#[napi(no_export)] can only be applied to a function."
+      );
+    }
     let napi = self.convert_to_ast(opts);
     self.to_tokens(tokens);
     napi

crates/napi/src/bindgen_runtime/module_register.rs

@@ -94,12 +94,6 @@ impl ModuleClassProperty {
   }
 }
 
-type FnRegisterMap = PersistedPerInstanceHashMap<
-  ExportRegisterCallback,
-  (sys::napi_callback, &'static str),
-  FxBuildHasher,
->;
-
 #[cfg(not(feature = "noop"))]
 static MODULE_REGISTER_CALLBACK: LazyLock<ModuleRegisterCallback> = LazyLock::new(Default::default);
 #[cfg(not(feature = "noop"))]
@@ -113,7 +107,6 @@ static MODULE_COUNT: AtomicUsize = AtomicUsize::new(0);
 static FIRST_MODULE_REGISTERED: AtomicBool = AtomicBool::new(false);
 thread_local! {
   static REGISTERED_CLASSES: LazyCell<RegisteredClasses> = LazyCell::new(Default::default);
-  static FN_REGISTER_MAP: LazyCell<FnRegisterMap> = LazyCell::new(Default::default);
 }
 #[cfg(all(feature = "napi4", not(feature = "noop")))]
 pub(crate) static CUSTOM_GC_TSFN: std::sync::atomic::AtomicPtr<sys::napi_threadsafe_function__> =
@@ -194,19 +187,6 @@ pub fn register_module_export_hook(cb: ExportRegisterHookCallback) {
 #[doc(hidden)]
 pub fn register_module_export_hook(_cb: ExportRegisterHookCallback) {}
 
-#[doc(hidden)]
-pub fn register_js_function(
-  name: &'static str,
-  cb: ExportRegisterCallback,
-  c_fn: sys::napi_callback,
-) {
-  FN_REGISTER_MAP.with(|cell| {
-    cell.borrow_mut(|inner| {
-      inner.insert(cb, (c_fn, name));
-    })
-  });
-}
-
 #[doc(hidden)]
 pub fn get_class_constructor(js_name: &'static str) -> Option<sys::napi_ref> {
   REGISTERED_CLASSES.with(|cell| cell.borrow_mut(|map| map.get(js_name).copied()))
@@ -239,41 +219,6 @@ pub fn register_class(
 ) {
 }
 
-/// Get `C Callback` from defined Rust `fn`
-/// ```rust
-/// #[napi]
-/// fn some_fn() -> u32 {
-///     1
-/// }
-///
-/// #[napi]
-/// fn create_obj(env: Env) -> Result<JsObject> {
-///     let mut obj = env.create_object()?;
-///     obj.define_property(&[Property::new("getter")?.with_getter(get_c_callback(some_fn_js_function)?)])?;
-///     Ok(obj)
-/// }
-/// ```
-///
-/// ```js
-/// console.log(createObj().getter) // 1
-/// ```
-///
-pub fn get_c_callback(raw_fn: ExportRegisterCallback) -> Result<crate::Callback> {
-  FN_REGISTER_MAP.with(|cell| {
-    cell.borrow_mut(|inner| {
-      inner
-        .get(&raw_fn)
-        .and_then(|(cb, _name)| *cb)
-        .ok_or_else(|| {
-          crate::Error::new(
-            crate::Status::InvalidArg,
-            "JavaScript function does not exist".to_owned(),
-          )
-        })
-    })
-  })
-}
-
 #[cfg(all(target_family = "wasm", not(feature = "noop")))]
 #[no_mangle]
 unsafe extern "C" fn napi_register_wasm_v1(

examples/napi/__tests__/__snapshots__/values.spec.ts.md

@@ -497,6 +497,8 @@ Generated by [AVA](https://avajs.dev).
     ␊
     export declare function createExternalTypedArray(): Uint32Array␊
     ␊
+    export declare function createFunction(): (arg: number) => number␊
+    ␊
     export declare function createObj(): object␊
     ␊
     export declare function createObjectRef(): object␊
@@ -573,7 +575,7 @@ Generated by [AVA](https://avajs.dev).
     ␊
     export declare function either4(input: string | number | boolean | Obj): number␊
     ␊
-    export declare function eitherBoolOrFunction(input: boolean | (any)): void␊
+    export declare function eitherBoolOrFunction(input: boolean | ((arg?: unknown) => unknown)): void␊
     ␊
     export declare function eitherBoolOrTuple(input: boolean | [boolean, string]): void␊
     ␊
@@ -934,7 +936,7 @@ Generated by [AVA](https://avajs.dev).
     ␊
     export declare function testSerdeRoundtrip(data: any): any␊
     ␊
-    export declare function threadsafeFunctionBuildThrowErrorWithStatus(cb: any): void␊
+    export declare function threadsafeFunctionBuildThrowErrorWithStatus(cb: (arg?: unknown) => unknown): void␊
     ␊
     export declare function threadsafeFunctionClosureCapture(defaultValue: Animal, func: (arg: Animal) => void): void␊
     ␊

examples/napi/__tests__/values.spec.ts

@@ -196,6 +196,7 @@ import {
   type AliasedStruct,
   returnObjectOnlyToJs,
   buildThreadsafeFunctionFromFunction,
+  buildThreadsafeFunctionFromFunctionCalleeHandle,
   createOptionalExternal,
   getOptionalExternal,
   mutateOptionalExternal,
@@ -255,6 +256,7 @@ import {
   uint8ArrayFromExternal,
   Thing,
   ThingList,
+  createFunction,
 } from '../index.cjs'
 // import other stuff in `#[napi(module_exports)]`
 import nativeAddon from '../index.cjs'
@@ -424,6 +426,8 @@ test('function call', async (t) => {
     referenceAsCallback((a, b) => a + b, 42, 10),
     52,
   )
+  const fn = createFunction()
+  t.is(fn(42), 242)
 })
 
 test('class', (t) => {
@@ -1667,6 +1671,10 @@ Napi4Test('build ThreadsafeFunction from Function', (t) => {
 
   buildThreadsafeFunctionFromFunction(fn)
 
+  t.notThrows(() => {
+    buildThreadsafeFunctionFromFunctionCalleeHandle(() => {})
+  })
+
   return subject.pipe(take(3))
 })
 

examples/napi/example.wasi-browser.js

@@ -185,6 +185,7 @@ export const createExternalBufferSlice = __napiModule.exports.createExternalBuff
 export const createExternalRef = __napiModule.exports.createExternalRef
 export const createExternalString = __napiModule.exports.createExternalString
 export const createExternalTypedArray = __napiModule.exports.createExternalTypedArray
+export const createFunction = __napiModule.exports.createFunction
 export const createObj = __napiModule.exports.createObj
 export const createObjectRef = __napiModule.exports.createObjectRef
 export const createObjectWithClassField = __napiModule.exports.createObjectWithClassField

examples/napi/example.wasi.cjs

@@ -209,6 +209,7 @@ module.exports.createExternalBufferSlice = __napiModule.exports.createExternalBu
 module.exports.createExternalRef = __napiModule.exports.createExternalRef
 module.exports.createExternalString = __napiModule.exports.createExternalString
 module.exports.createExternalTypedArray = __napiModule.exports.createExternalTypedArray
+module.exports.createFunction = __napiModule.exports.createFunction
 module.exports.createObj = __napiModule.exports.createObj
 module.exports.createObjectRef = __napiModule.exports.createObjectRef
 module.exports.createObjectWithClassField = __napiModule.exports.createObjectWithClassField

examples/napi/index.cjs

@@ -500,6 +500,7 @@ module.exports.createExternalBufferSlice = nativeBinding.createExternalBufferSli
 module.exports.createExternalRef = nativeBinding.createExternalRef
 module.exports.createExternalString = nativeBinding.createExternalString
 module.exports.createExternalTypedArray = nativeBinding.createExternalTypedArray
+module.exports.createFunction = nativeBinding.createFunction
 module.exports.createObj = nativeBinding.createObj
 module.exports.createObjectRef = nativeBinding.createObjectRef
 module.exports.createObjectWithClassField = nativeBinding.createObjectWithClassField

examples/napi/index.d.cts

@@ -459,6 +459,8 @@ export declare function createExternalString(content: string): ExternalObject<st
 
 export declare function createExternalTypedArray(): Uint32Array
 
+export declare function createFunction(): (arg: number) => number
+
 export declare function createObj(): object
 
 export declare function createObjectRef(): object
@@ -535,7 +537,7 @@ export declare function either3(input: string | number | boolean): number
 
 export declare function either4(input: string | number | boolean | Obj): number
 
-export declare function eitherBoolOrFunction(input: boolean | (any)): void
+export declare function eitherBoolOrFunction(input: boolean | ((arg?: unknown) => unknown)): void
 
 export declare function eitherBoolOrTuple(input: boolean | [boolean, string]): void
 
@@ -896,7 +898,7 @@ export declare function testSerdeBufferBytes(obj: object): bigint
 
 export declare function testSerdeRoundtrip(data: any): any
 
-export declare function threadsafeFunctionBuildThrowErrorWithStatus(cb: any): void
+export declare function threadsafeFunctionBuildThrowErrorWithStatus(cb: (arg?: unknown) => unknown): void
 
 export declare function threadsafeFunctionClosureCapture(defaultValue: Animal, func: (arg: Animal) => void): void
 

examples/napi/src/function.rs

@@ -1,5 +1,3 @@
-#![allow(deprecated)]
-
 use napi::{
   bindgen_prelude::{ClassInstance, FnArgs, Function, FunctionRef, PromiseRaw},
   threadsafe_function::ThreadsafeFunctionCallMode,
@@ -140,3 +138,13 @@ pub fn build_threadsafe_function_from_function_callee_handle(
 
   Ok(())
 }
+
+#[napi]
+pub fn create_function(env: &Env) -> Result<Function<u32, u32>> {
+  env.create_function("customFunction", no_export_function_c_callback)
+}
+
+#[napi(no_export)]
+pub fn no_export_function(input: u32) -> u32 {
+  input + 200
+}

examples/napi/src/object.rs

@@ -96,7 +96,7 @@ pub fn create_obj_with_property(env: &Env) -> Result<Object<'_>> {
       .with_value(&arraybuffer),
     Property::new()
       .with_utf8_name("getter")?
-      .with_getter(get_c_callback(getter_from_obj_js_function)?),
+      .with_getter(getter_from_obj_c_callback),
   ])?;
   Ok(obj)
 }