refine value provider check if user passes a 'undefined' value

src/__tests__/global-container.test.ts

@@ -553,6 +553,13 @@ test("registers by value provider", () => {
   expect(globalContainer.isRegistered(registration.token)).toBeTruthy();
 });
 
+test("value provider with 'undefined' value should work fine", () => {
+  globalContainer.register("Foo", {
+    useValue: undefined
+  });
+  expect(globalContainer.resolve("Foo")).toBe(undefined);
+});
+
 test("registers by token provider", () => {
   const registration = {
     token: "IBar",

src/providers/value-provider.ts

@@ -7,5 +7,5 @@ export default interface ValueProvider<T> {
 export function isValueProvider<T>(
   provider: Provider<T>
 ): provider is ValueProvider<T> {
-  return (provider as ValueProvider<T>).useValue != undefined;
+  return Object.prototype.hasOwnProperty.call(provider, "useValue");
 }