fix: Use function wrapper provided by JS

wasm/function.go

@@ -27,7 +27,7 @@ func toJSFunc(x reflect.Value) js.Value {
 		hasError = funcType.Out(funcType.NumOut()-1) == errorType
 	}
 
-	return js.FuncOf(func(this js.Value, args []js.Value) interface{} {
+	return funcWrapper.Invoke(js.FuncOf(func(this js.Value, args []js.Value) interface{} {
 		in, err := conformJSValueToType(funcType, this, args)
 		if err != nil {
 			return ToJSValue(goThrowable{
@@ -52,7 +52,7 @@ func toJSFunc(x reflect.Value) js.Value {
 		return ToJSValue(goThrowable{
 			Result: returnValue(out[:len(out)-1]),
 		})
-	}).JSValue()
+	}))
 }
 
 var jsValueType = reflect.TypeOf(js.Value{})

wasm/wasm.go

@@ -1,12 +1,18 @@
 package wasm
 
+import "syscall/js"
+
 // Magic values to communicate with the JS library.
 const (
 	globalIdent     = "__go_wasm__"
 	readyHint       = "__ready__"
+	funcWrapperName = "__wrapper__"
 )
 
-var bridge Object
+var (
+	bridge      Object
+	funcWrapper js.Value
+)
 
 func init() {
 	bridgeJS, err := Global().Get(globalIdent)
@@ -18,6 +24,11 @@ func init() {
 	if err != nil {
 		panic("JS wrapper " + globalIdent + " is not an object")
 	}
+
+	funcWrapper, err = bridge.Get(funcWrapperName)
+	if err != nil {
+		panic("JS wrapper " + globalIdent + "." + funcWrapperName + " not found")
+	}
 }
 
 // Ready notifies the JS bridge that the WASM is ready.