chore: added message types to PubSub Service

packages/hoppscotch-backend/src/pubsub/pubsub.service.ts

@@ -4,6 +4,7 @@ import { default as Redis, RedisOptions } from 'ioredis';
 
 import { RedisPubSub } from 'graphql-redis-subscriptions';
 import { PubSub as LocalPubSub } from 'graphql-subscriptions';
+import { MessageType } from './subscriptionTopicsDefs';
 
 /**
  * RedisPubSub uses JSON parsing for back and forth conversion, which loses Date objects, hence this reviver brings them back
@@ -70,7 +71,10 @@ export class PubSubService implements OnModuleInit {
     return this.pubsub.asyncIterator(topic, options);
   }
 
-  async publish(topic: string, payload: any) {
+  async publish<T extends keyof MessageType>(
+    topic: T,
+    payload: MessageType[T],
+  ) {
     await this.pubsub.publish(topic, payload);
   }
 }

packages/hoppscotch-backend/src/pubsub/subscriptionTopicsDefs.ts

@@ -0,0 +1,14 @@
+import { UserEnvironment } from '../user-environment/user-environments.model';
+import { PrimitiveTypes } from '../types/primitiveTypes';
+
+// A custom message type that defines the topic and the corresponding payload.
+// For every module that publishes a subscription add its type def and the possible subscription type.
+export type MessageType = {
+  [
+    topic: `user_environment/${string}/${
+      | 'created'
+      | 'updated'
+      | 'deleted'
+      | 'deleted_many'}`
+  ]: UserEnvironment | PrimitiveTypes; // Returning a number hence having a union with `PrimitiveTypes`.
+};