feat(core): implement Deno.core.isProxy() (#12288)

core/bindings.rs

@@ -67,6 +67,9 @@ lazy_static::lazy_static! {
       v8::ExternalReference {
         function: get_proxy_details.map_fn_to()
       },
+      v8::ExternalReference {
+        function: is_proxy.map_fn_to()
+      },
       v8::ExternalReference {
         function: memory_usage.map_fn_to(),
       },
@@ -151,6 +154,7 @@ pub fn initialize_context<'s>(
   set_func(scope, core_val, "deserialize", deserialize);
   set_func(scope, core_val, "getPromiseDetails", get_promise_details);
   set_func(scope, core_val, "getProxyDetails", get_proxy_details);
+  set_func(scope, core_val, "isProxy", is_proxy);
   set_func(scope, core_val, "memoryUsage", memory_usage);
   set_func(scope, core_val, "callConsole", call_console);
   set_func(scope, core_val, "createHostObject", create_host_object);
@@ -1137,6 +1141,14 @@ fn get_proxy_details(
   rv.set(to_v8(scope, p).unwrap());
 }
 
+fn is_proxy(
+  scope: &mut v8::HandleScope,
+  args: v8::FunctionCallbackArguments,
+  mut rv: v8::ReturnValue,
+) {
+  rv.set(v8::Boolean::new(scope, args.get(0).is_proxy()).into())
+}
+
 fn throw_type_error(scope: &mut v8::HandleScope, message: impl AsRef<str>) {
   let message = v8::String::new(scope, message.as_ref()).unwrap();
   let exception = v8::Exception::type_error(scope, message);

core/runtime.rs

@@ -2263,4 +2263,25 @@ assertEquals(1, notify_return_value);
     let mut runtime = JsRuntime::new(options);
     runtime.execute_script("<none>", "").unwrap();
   }
+
+  #[test]
+  fn test_is_proxy() {
+    let mut runtime = JsRuntime::new(RuntimeOptions::default());
+    let all_true: v8::Global<v8::Value> = runtime
+      .execute_script(
+        "is_proxy.js",
+        r#"
+      (function () {
+        const { isProxy } = Deno.core;
+        const o = { a: 1, b: 2};
+        const p = new Proxy(o, {});
+        return isProxy(p) && !isProxy(o) && !isProxy(42);
+      })()
+    "#,
+      )
+      .unwrap();
+    let mut scope = runtime.handle_scope();
+    let all_true = v8::Local::<v8::Value>::new(&mut scope, &all_true);
+    assert!(all_true.is_true());
+  }
 }