diff --git a/crates/napi/src/env.rs b/crates/napi/src/env.rs
index 0a54e929..6b957871 100644
--- a/crates/napi/src/env.rs
+++ b/crates/napi/src/env.rs
@@ -1,10 +1,14 @@
 use std::any::TypeId;
 use std::convert::TryInto;
 use std::ffi::CString;
+#[cfg(all(feature = "tokio_rt", feature = "napi4"))]
+use std::future::Future;
 use std::mem;
 use std::os::raw::{c_char, c_void};
 use std::ptr;
 
+#[cfg(all(feature = "tokio_rt", feature = "napi4"))]
+use crate::bindgen_runtime::ToNapiValue;
 use crate::{
   async_work::{self, AsyncWorkPromise},
   check_status,
@@ -28,8 +32,6 @@ use crate::JsError;
 use serde::de::DeserializeOwned;
 #[cfg(all(feature = "serde-json"))]
 use serde::Serialize;
-#[cfg(all(feature = "tokio_rt", feature = "napi4"))]
-use std::future::Future;
 
 pub type Callback = unsafe extern "C" fn(sys::napi_env, sys::napi_callback_info) -> sys::napi_value;
 
@@ -1038,7 +1040,7 @@ impl Env {
   #[cfg(feature = "napi4")]
   pub fn create_threadsafe_function<
     T: Send,
-    V: NapiRaw,
+    V: ToNapiValue,
     R: 'static + Send + FnMut(ThreadSafeCallContext<T>) -> Result<Vec<V>>,
   >(
     &self,
@@ -1052,7 +1054,7 @@ impl Env {
   #[cfg(all(feature = "tokio_rt", feature = "napi4"))]
   pub fn execute_tokio_future<
     T: 'static + Send,
-    V: 'static + NapiValue,
+    V: 'static + ToNapiValue,
     F: 'static + Send + Future<Output = Result<T>>,
     R: 'static + Send + Sync + FnOnce(&mut Env, T) -> Result<V>,
   >(
@@ -1063,7 +1065,7 @@ impl Env {
     use crate::tokio_runtime;
 
     let promise = tokio_runtime::execute_tokio_future(self.0, fut, |env, val| unsafe {
-      resolver(&mut Env::from_raw(env), val).map(|v| v.raw())
+      resolver(&mut Env::from_raw(env), val).and_then(|v| ToNapiValue::to_napi_value(env, v))
     })?;
 
     Ok(unsafe { JsObject::from_raw_unchecked(self.0, promise) })
diff --git a/crates/napi/src/js_values/function.rs b/crates/napi/src/js_values/function.rs
index 12c4f4b9..f6dfa5f6 100644
--- a/crates/napi/src/js_values/function.rs
+++ b/crates/napi/src/js_values/function.rs
@@ -3,7 +3,10 @@ use std::ptr;
 use super::Value;
 use crate::bindgen_runtime::TypeName;
 #[cfg(feature = "napi4")]
-use crate::threadsafe_function::{ThreadSafeCallContext, ThreadsafeFunction};
+use crate::{
+  bindgen_runtime::ToNapiValue,
+  threadsafe_function::{ThreadSafeCallContext, ThreadsafeFunction},
+};
 use crate::{check_status, ValueType};
 use crate::{sys, Env, Error, JsObject, JsUnknown, NapiRaw, NapiValue, Result, Status};
 
@@ -127,7 +130,7 @@ impl JsFunction {
   ) -> Result<ThreadsafeFunction<T, ES>>
   where
     T: 'static,
-    V: NapiRaw,
+    V: ToNapiValue,
     F: 'static + Send + FnMut(ThreadSafeCallContext<T>) -> Result<Vec<V>>,
     ES: crate::threadsafe_function::ErrorStrategy::T,
   {
diff --git a/crates/napi/src/threadsafe_function.rs b/crates/napi/src/threadsafe_function.rs
index 025028ad..3f0dbb9a 100644
--- a/crates/napi/src/threadsafe_function.rs
+++ b/crates/napi/src/threadsafe_function.rs
@@ -8,7 +8,8 @@ use std::ptr;
 use std::sync::atomic::{AtomicBool, AtomicUsize, Ordering};
 use std::sync::Arc;
 
-use crate::{check_status, sys, Env, Error, JsError, NapiRaw, Result, Status};
+use crate::bindgen_runtime::ToNapiValue;
+use crate::{check_status, sys, Env, Error, JsError, Result, Status};
 
 /// ThreadSafeFunction Context object
 /// the `value` is the value passed to `call` method
@@ -176,7 +177,7 @@ impl<T: 'static, ES: ErrorStrategy::T> ThreadsafeFunction<T, ES> {
   /// See [napi_create_threadsafe_function](https://nodejs.org/api/n-api.html#n_api_napi_create_threadsafe_function)
   /// for more information.
   pub(crate) fn create<
-    V: NapiRaw,
+    V: ToNapiValue,
     R: 'static + Send + FnMut(ThreadSafeCallContext<T>) -> Result<Vec<V>>,
   >(
     env: sys::napi_env,
@@ -330,7 +331,7 @@ unsafe extern "C" fn cleanup_cb(cleanup_data: *mut c_void) {
   aborted.store(true, Ordering::SeqCst);
 }
 
-unsafe extern "C" fn thread_finalize_cb<T: 'static, V: NapiRaw, R>(
+unsafe extern "C" fn thread_finalize_cb<T: 'static, V: ToNapiValue, R>(
   _raw_env: sys::napi_env,
   finalize_data: *mut c_void,
   _finalize_hint: *mut c_void,
@@ -341,7 +342,7 @@ unsafe extern "C" fn thread_finalize_cb<T: 'static, V: NapiRaw, R>(
   drop(unsafe { Box::<R>::from_raw(finalize_data.cast()) });
 }
 
-unsafe extern "C" fn call_js_cb<T: 'static, V: NapiRaw, R, ES>(
+unsafe extern "C" fn call_js_cb<T: 'static, V: ToNapiValue, R, ES>(
   raw_env: sys::napi_env,
   js_callback: sys::napi_value,
   context: *mut c_void,
@@ -378,23 +379,42 @@ unsafe extern "C" fn call_js_cb<T: 'static, V: NapiRaw, R, ES>(
   // If the Result is an error, pass that as the first argument.
   let status = match ret {
     Ok(values) => {
-      let values = values.iter().map(|v| unsafe { v.raw() });
-      let args: Vec<sys::napi_value> = if ES::VALUE == ErrorStrategy::CalleeHandled::VALUE {
+      let values = values
+        .into_iter()
+        .map(|v| unsafe { ToNapiValue::to_napi_value(raw_env, v) });
+      let args: Result<Vec<sys::napi_value>> = if ES::VALUE == ErrorStrategy::CalleeHandled::VALUE {
         let mut js_null = ptr::null_mut();
         unsafe { sys::napi_get_null(raw_env, &mut js_null) };
-        ::core::iter::once(js_null).chain(values).collect()
+        ::core::iter::once(Ok(js_null)).chain(values).collect()
       } else {
         values.collect()
       };
-      unsafe {
-        sys::napi_call_function(
-          raw_env,
-          recv,
-          js_callback,
-          args.len(),
-          args.as_ptr(),
-          ptr::null_mut(),
-        )
+      match args {
+        Ok(args) => unsafe {
+          sys::napi_call_function(
+            raw_env,
+            recv,
+            js_callback,
+            args.len(),
+            args.as_ptr(),
+            ptr::null_mut(),
+          )
+        },
+        Err(e) => match ES::VALUE {
+          ErrorStrategy::Fatal::VALUE => unsafe {
+            sys::napi_fatal_exception(raw_env, JsError::from(e).into_value(raw_env))
+          },
+          ErrorStrategy::CalleeHandled::VALUE => unsafe {
+            sys::napi_call_function(
+              raw_env,
+              recv,
+              js_callback,
+              1,
+              [JsError::from(e).into_value(raw_env)].as_mut_ptr(),
+              ptr::null_mut(),
+            )
+          },
+        },
       }
     }
     Err(e) if ES::VALUE == ErrorStrategy::Fatal::VALUE => unsafe {
diff --git a/examples/napi/src/callback.rs b/examples/napi/src/callback.rs
index 52f1269b..14793f61 100644
--- a/examples/napi/src/callback.rs
+++ b/examples/napi/src/callback.rs
@@ -1,6 +1,10 @@
 use std::env;
 
-use napi::bindgen_prelude::*;
+use napi::{
+  bindgen_prelude::*,
+  threadsafe_function::{ThreadSafeCallContext, ThreadsafeFunction, ThreadsafeFunctionCallMode},
+  JsUnknown,
+};
 
 #[napi]
 fn get_cwd<T: Fn(String) -> Result<()>>(callback: T) {
@@ -46,3 +50,32 @@ fn read_file_content() -> Result<String> {
 fn return_js_function(env: Env) -> Result<JsFunction> {
   get_js_function(&env, read_file_js_function)
 }
+
+#[napi(
+  ts_generic_types = "T",
+  ts_args_type = "functionInput: () => T | Promise<T>, callback: (err: Error | null, result: T) => void"
+)]
+fn callback_return_promise<T: Fn() -> Result<JsUnknown>>(
+  env: Env,
+  fn_in: T,
+  fn_out: JsFunction,
+) -> Result<JsUnknown> {
+  let ret = fn_in()?;
+  if ret.is_promise()? {
+    let p = Promise::<String>::from_unknown(ret)?;
+    let fn_out_tsfn: ThreadsafeFunction<String> = fn_out
+      .create_threadsafe_function(0, |ctx: ThreadSafeCallContext<String>| Ok(vec![ctx.value]))?;
+    env
+      .execute_tokio_future(
+        async move {
+          let s = p.await;
+          fn_out_tsfn.call(s, ThreadsafeFunctionCallMode::NonBlocking);
+          Ok::<(), Error>(())
+        },
+        |env, _| env.get_undefined(),
+      )
+      .map(|v| v.into_unknown())
+  } else {
+    Ok(ret)
+  }
+}