feat(napi-derive): implement instance_of for Class

crates/backend/src/codegen/struct.rs

@@ -283,6 +283,7 @@ impl NapiStruct {
     } else {
       quote! { impl napi::bindgen_prelude::ObjectFinalize for #name {} }
     };
+    let instance_of_impl = self.gen_instance_of_impl(name, &js_name_str);
     quote! {
       impl napi::bindgen_prelude::ToNapiValue for #name {
         unsafe fn to_napi_value(
@@ -303,7 +304,7 @@ impl NapiStruct {
       }
 
       #finalize_trait
-
+      #instance_of_impl
       impl #name {
         pub fn into_reference(val: #name, env: napi::Env) -> napi::Result<napi::bindgen_prelude::Reference<#name>> {
           if let Some(ctor_ref) = napi::bindgen_prelude::get_class_constructor(#js_name_str) {
@@ -394,6 +395,7 @@ impl NapiStruct {
     let name = &self.name;
     let js_name_without_null = &self.js_name;
     let js_name_str = format!("{}\0", &self.js_name);
+    let instance_of_impl = self.gen_instance_of_impl(name, &js_name_str);
 
     let mut field_conversions = vec![];
     let mut field_destructions = vec![];
@@ -466,7 +468,7 @@ impl NapiStruct {
           }
         }
       }
-
+      #instance_of_impl
       #finalize_trait
     }
   }
@@ -750,6 +752,32 @@ impl NapiStruct {
       }
     }
   }
+
+  fn gen_instance_of_impl(&self, name: &Ident, js_name: &str) -> TokenStream {
+    quote! {
+      impl #name {
+        pub fn instance_of<V: napi::NapiRaw>(env: napi::Env, value: V) -> napi::Result<bool> {
+          if let Some(ctor_ref) = napi::bindgen_prelude::get_class_constructor(#js_name) {
+            let mut ctor = std::ptr::null_mut();
+            napi::check_status!(
+              unsafe { napi::sys::napi_get_reference_value(env.raw(), ctor_ref, &mut ctor) },
+              "Failed to get constructor reference of class `{}`",
+              #js_name
+            )?;
+            let mut is_instance_of = false;
+            napi::check_status!(
+              unsafe { napi::sys::napi_instanceof(env.raw(), value.raw(), ctor, &mut is_instance_of) },
+              "Failed to run instanceof for class `{}`",
+              #js_name
+            )?;
+            Ok(is_instance_of)
+          } else {
+            Err(napi::Error::new(napi::Status::GenericFailure, format!("Failed to get constructor of class `{}`", #js_name)))
+          }
+        }
+      }
+    }
+  }
 }
 
 impl TryToTokens for NapiImpl {

examples/napi/__test__/typegen.spec.ts.md

@@ -267,6 +267,7 @@ Generated by [AVA](https://avajs.dev).
     }␊
     export class NinjaTurtle {␊
       name: string␊
+      static isInstanceOf(value: unknown): boolean␊
       /** Create your ninja turtle! 🐢 */␊
       static newRaph(): NinjaTurtle␊
       getMaskColor(): string␊

examples/napi/__test__/values.spec.ts

@@ -191,6 +191,7 @@ test('class', (t) => {
   t.is(assets.get(1)?.filePath, 1)
   const turtle = NinjaTurtle.newRaph()
   t.is(turtle.returnThis(), turtle)
+  t.is(NinjaTurtle.isInstanceOf(turtle), true)
 })
 
 test('class factory', (t) => {

examples/napi/index.d.ts

@@ -257,6 +257,7 @@ export class AnimalWithDefaultConstructor {
 }
 export class NinjaTurtle {
   name: string
+  static isInstanceOf(value: unknown): boolean
   /** Create your ninja turtle! 🐢 */
   static newRaph(): NinjaTurtle
   getMaskColor(): string

examples/napi/src/class.rs

@@ -1,5 +1,5 @@
 use napi::{
-  bindgen_prelude::{Buffer, ClassInstance, ObjectFinalize, This, Uint8Array},
+  bindgen_prelude::{Buffer, ClassInstance, ObjectFinalize, This, Uint8Array, Unknown},
   Env, Result,
 };
 
@@ -214,6 +214,11 @@ pub struct NinjaTurtle {
 
 #[napi]
 impl NinjaTurtle {
+  #[napi]
+  pub fn is_instance_of(env: Env, value: Unknown) -> Result<bool> {
+    Self::instance_of(env, value)
+  }
+
   /// Create your ninja turtle! 🐢
   #[napi(factory)]
   pub fn new_raph() -> Self {