Merge pull request #2 from risen228/fix/205-value-provider-check

Fix value provider check

src/__tests__/global-container.test.ts

@@ -556,6 +556,14 @@ 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 type ValueProvider<T> = {
 export function isValueProvider<T>(
   provider: Provider<T>,
 ): provider is ValueProvider<T> {
-  return (provider as ValueProvider<T>).useValue != null
+  return Object.prototype.hasOwnProperty.call(provider, 'useValue')
 }