chore(example): add callback return promise (#1590)

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

@@ -256,6 +256,8 @@ Generated by [AVA](https://avajs.dev).
     ␊
     export function callbackReturnPromise<T>(functionInput: () => T | Promise<T>, callback: (err: Error | null, result: T) => void): T | Promise<T>␊
     ␊
+    export function callbackReturnPromiseAndSpawn(jsFunc: (arg0: string) => Promise<string>): Promise<string>␊
+    ␊
     export function callLongThreadsafeFunction(callback: (...args: any[]) => any): void␊
     ␊
     export function callThreadsafeFunction(callback: (...args: any[]) => any): void␊

examples/napi/__tests__/values.spec.ts

@@ -104,6 +104,7 @@ import {
   CssStyleSheet,
   asyncReduceBuffer,
   callbackReturnPromise,
+  callbackReturnPromiseAndSpawn,
   returnEitherClass,
   eitherFromOption,
   eitherFromObjects,
@@ -348,6 +349,13 @@ test('callback function return Promise', async (t) => {
   t.deepEqual(cbSpy.args, [['42']])
 })
 
+test('callback function return Promise and spawn', async (t) => {
+  const finalReturn = await callbackReturnPromiseAndSpawn((input) =>
+    Promise.resolve(`${input} world`),
+  )
+  t.is(finalReturn, 'Hello world 😼')
+})
+
 test('object', (t) => {
   t.deepEqual(listObjKeys({ name: 'John Doe', age: 20 }), ['name', 'age'])
   t.deepEqual(createObj(), { test: 1 })

examples/napi/index.d.ts

@@ -246,6 +246,8 @@ export interface C {
 
 export function callbackReturnPromise<T>(functionInput: () => T | Promise<T>, callback: (err: Error | null, result: T) => void): T | Promise<T>
 
+export function callbackReturnPromiseAndSpawn(jsFunc: (arg0: string) => Promise<string>): Promise<string>
+
 export function callLongThreadsafeFunction(callback: (...args: any[]) => any): void
 
 export function callThreadsafeFunction(callback: (...args: any[]) => any): void

examples/napi/src/callback.rs

@@ -1,4 +1,4 @@
-use std::env;
+use std::{env, format};
 
 use napi::{
   bindgen_prelude::*,
@@ -81,6 +81,18 @@ fn callback_return_promise<T: Fn() -> Result<JsUnknown>>(
   }
 }
 
+#[napi(ts_return_type = "Promise<string>")]
+pub fn callback_return_promise_and_spawn<F: Fn(String) -> Result<Promise<String>>>(
+  env: Env,
+  js_func: F,
+) -> napi::Result<Object> {
+  let promise = js_func("Hello".to_owned())?;
+  env.spawn_future(async move {
+    let resolved = promise.await?;
+    Ok::<String, napi::Error>(format!("{} 😼", resolved))
+  })
+}
+
 #[napi]
 pub fn capture_error_in_callback<C: Fn() -> Result<()>, E: Fn(Error) -> Result<()>>(
   cb1: C,