fix(core): properly handle function without prototype in reflector (#22284)

closes #19978 PR Close #22284

Author: trotyl

packages/core/src/reflection/reflection_capabilities.ts

@@ -252,7 +252,7 @@ function convertTsickleDecoratorIntoMetadata(decoratorInvocations: any[]): any[]
 }
 
 function getParentCtor(ctor: Function): Type<any> {
- const parentProto = Object.getPrototypeOf(ctor.prototype);
+ const parentProto = ctor.prototype ? Object.getPrototypeOf(ctor.prototype) : null;
  const parentCtor = parentProto ? parentProto.constructor : null;
  // Note: We always use `Object` as the null value
  // to simplify checking later on.

packages/core/test/reflection/reflector_spec.ts

@@ -181,6 +181,13 @@ class TestObj {
  expect(DELEGATE_CTOR.exec(ChildNoCtorPrivateProps.toString())).toBeTruthy();
  expect(DELEGATE_CTOR.exec(ChildWithCtor.toString())).toBeFalsy();
  });
+
+ it('should not throw when no prototype on type', () => {
+ // Cannot test arrow function here due to the compilation
+ const dummyArrowFn = function() {};
+ Object.defineProperty(dummyArrowFn, 'prototype', {value: undefined});
+ expect(() => reflector.annotations(dummyArrowFn as any)).not.toThrow();
+ });
  });
 
  describe('inheritance with decorators', () => {