docs(docs.nestjs.com) show example of enabling Throttle rate limiting behind proxies with express

the documentation was unsufficient to succesfuly implement the throttling since the external link
to express suggested using 'app.set' method,  wich by default  throws
'property set does not exist` error

Author: lukaszniemkiewicz

.swp

@@ -72,7 +72,23 @@ findAll() {
 
 #### Proxies
 
-If your application runs behind a proxy server, check the specific HTTP adapter options ([express](http://expressjs.com/en/guide/behind-proxies.html) and [fastify](https://www.fastify.io/docs/latest/Reference/Server/#trustproxy)) for the `trust proxy` option and enable it. Doing so will allow you to get the original IP address from the `X-Forwarded-For` header, and you can override the `getTracker()` method to pull the value from the header rather than from `req.ip`. The following example works with both express and fastify:
+If your application runs behind a proxy server, check the specific HTTP adapter options ([express](http://expressjs.com/en/guide/behind-proxies.html) and [fastify](https://www.fastify.io/docs/latest/Reference/Server/#trustproxy)) for the `trust proxy` option and enable it. 
+Following example enables `trust proxy` for express adapter:
+
+```typescript
+//main.ts
+import { NestFactory } from '@nestjs/core';
+import { AppModule } from './app.module';
+import { NestExpressApplication } from "@nestjs/platform-express"
+async function bootstrap() {
+  const app = await NestFactory.create<NestExpressApplication>(AppModule);
+  app.set('trust proxy', 'loopback') // specify a single subnet
+  await app.listen(3000)
+}
+bootstrap();
+```
+
+Doing so will allow you to get the original IP address from the `X-Forwarded-For` header, and you can override the `getTracker()` method to pull the value from the header rather than from `req.ip`. The following example works with both express and fastify:
 
 ```typescript
 // throttler-behind-proxy.guard.ts