Return the result of Proc when it's called as JS closure

Somehow, the return value of the Proc was not returned to the JS side.

Author: kateinoigakukun

packages/gems/js/lib/js.rb

@@ -79,8 +79,8 @@ def await(promise)
       current = Fiber.current
       promise.call(
         :then,
-        ->(value) { current.transfer(value, :success) },
-        ->(value) { current.transfer(value, :failure) }
+        ->(value) { current.transfer(value, :success); nil },
+        ->(value) { current.transfer(value, :failure); nil }
       )
       if @loop == current
         raise (

packages/npm-packages/ruby-wasm-wasi/src/vm.ts

@@ -210,7 +210,7 @@ export class RubyVM {
         procToJsFunction: (rawRbAbiValue) => {
           const rbValue = this.rbValueOfPointer(rawRbAbiValue);
           return (...args) => {
-            rbValue.call("call", ...args.map((arg) => this.wrap(arg)));
+            return rbValue.call("call", ...args.map((arg) => this.wrap(arg))).toJS();
           };
         },
         rbObjectToJsRbValue: (rawRbAbiValue) => {

packages/npm-packages/ruby-wasm-wasi/test/unit/test_proc.rb

@@ -26,4 +26,11 @@ def test_store_in_js
     function_to_call.call(:invoke)
     assert_equal 1, b
   end
+
+  def test_return_value
+    obj = JS.eval(<<~JS)
+      return { check: (callback) => { return callback(1) } }
+    JS
+    assert_equal 4, obj.call(:check, ->(a) { 3 + a.to_i }).to_i
+  end
 end