prepare the server

src/main.ts

@@ -1,8 +1,15 @@
 import { NestFactory } from '@nestjs/core';
+import { ValidationPipe } from '@nestjs/common';
+import helmet from 'helmet';
 import { AppModule } from './app.module';
 
 async function bootstrap() {
   const app = await NestFactory.create(AppModule);
+
+  app.use(helmet());
+  app.enableCors();
+  app.useGlobalPipes(new ValidationPipe({ whitelist: true }));
+
   await app.listen(3000);
 }
 bootstrap();