fix(): property path is not detected issue #752

lib/config.service.ts

@@ -29,7 +29,7 @@ export interface ConfigGetOptions {
   infer: true;
 }
 
-type KeyOf<T> = T extends unknown ? string : keyof T;
+type KeyOf<T> = keyof T extends never ? string : keyof T;
 
 @Injectable()
 export class ConfigService<

lib/types/no-infer.type.ts

@@ -1,3 +1 @@
-export type NoInferType<T> = T extends unknown
-  ? any
-  : [T][T extends any ? 0 : never];
+export type NoInferType<T> = [T][T extends any ? 0 : never];

lib/types/path-value.type.ts

@@ -8,9 +8,7 @@ export type PathImpl<T, Key extends keyof T> = Key extends string
   : never;
 
 export type PathImpl2<T> = PathImpl<T, keyof T> | keyof T;
-export type Path<T> = T extends unknown
-  ? any
-  : PathImpl2<T> extends string | keyof T
+export type Path<T> = PathImpl2<T> extends string | keyof T
   ? PathImpl2<T>
   : keyof T;
 

tests/e2e/optional-generic.spec.ts

@@ -25,15 +25,17 @@ describe('Optional Generic()', () => {
 
   it(`should infer type from a dot notation`, () => {
     const configService =
-      moduleRef.get<ConfigService<{ obj: { test: boolean } }>>(ConfigService);
+      moduleRef.get<ConfigService<{ obj: { test: boolean; test2?: boolean } }>>(
+        ConfigService,
+      );
 
     const obj = configService.get('obj', { infer: true });
     const test = configService.get('obj.test', { infer: true });
-    const testWithDefaultValue = configService.get('obj.test', true, {
+    const testWithDefaultValue = configService.get('obj.test2', true, {
       infer: true,
     });
-    expect(obj?.test).toBeUndefined();
-    expect(test).toBeUndefined();
+    expect(obj?.test).toEqual('true');
+    expect(test).toEqual('true');
     expect(testWithDefaultValue).toBeTruthy();
   });
 

tests/src/app.module.ts

@@ -74,6 +74,7 @@ export class AppModule {
       imports: [
         ConfigModule.forRoot({
           envFilePath: join(__dirname, '.env'),
+          load: [() => ({ obj: { test: 'true', test2: undefined } })],
         }),
       ],
     };