feat(core): add method to verify factory provider

ensure isFactoryProvider returns true when useFactory is present

Author: thiagomini

packages/core/injector/helpers/provider-classifier.ts

@@ -1,4 +1,9 @@
-import { ClassProvider, Provider, ValueProvider } from '@nestjs/common';
+import {
+  ClassProvider,
+  FactoryProvider,
+  Provider,
+  ValueProvider,
+} from '@nestjs/common';
 
 export function isClassProvider(provider: Provider): boolean {
   return Boolean((provider as ClassProvider)?.useClass);
@@ -7,3 +12,7 @@ export function isClassProvider(provider: Provider): boolean {
 export function isValueProvider(provider: Provider): boolean {
   return Boolean((provider as ValueProvider)?.useValue);
 }
+
+export function isFactoryProvider(provider: Provider): boolean {
+  return Boolean((provider as FactoryProvider).useFactory);
+}

packages/core/test/injector/helpers/provider-classifier.spec.ts

@@ -1,7 +1,8 @@
-import { ClassProvider, ValueProvider } from '@nestjs/common';
+import { ClassProvider, FactoryProvider, ValueProvider } from '@nestjs/common';
 import { expect } from 'chai';
 import {
   isClassProvider,
+  isFactoryProvider,
   isValueProvider,
 } from '../../../injector/helpers/provider-classifier';
 
@@ -73,4 +74,15 @@ describe('provider classifier', () => {
       expect(isValueProvider(valueProvider as ValueProvider)).to.be.false;
     });
   });
+
+  describe('isFactoryProvider', () => {
+    it('should return true if useFactory is present', () => {
+      const factoryProvider: FactoryProvider = {
+        provide: 'token',
+        useFactory: () => {},
+      };
+
+      expect(isFactoryProvider(factoryProvider)).to.be.true;
+    });
+  });
 });