fix(microservices): when postfixId is an empty string on kafka

packages/microservices/client/client-kafka.ts

@@ -65,7 +65,7 @@ export class ClientKafka extends ClientProxy {
     const consumerOptions =
       this.getOptionsProp(this.options, 'consumer') || ({} as ConsumerConfig);
     const postfixId =
-      this.getOptionsProp(this.options, 'postfixId') ?? '-client';
+      this.getOptionsProp(this.options, 'postfixId', '-client', true);
     this.producerOnlyMode =
       this.getOptionsProp(this.options, 'producerOnlyMode') || false;
 
@@ -283,6 +283,14 @@ export class ClientKafka extends ClientProxy {
     }
   }
 
+  public getGroupId() {
+    return this.groupId
+  }
+
+  public getClientId() {
+    return this.clientId
+  }
+
   protected getResponsePatternName(pattern: string): string {
     return `${pattern}.reply`;
   }

packages/microservices/client/client-proxy.ts

@@ -129,8 +129,12 @@ export abstract class ClientProxy {
   protected getOptionsProp<
     T extends ClientOptions['options'],
     K extends keyof T,
-  >(obj: T, prop: K, defaultValue: T[K] = undefined) {
-    return (obj && obj[prop]) || defaultValue;
+  >(obj: T, prop: K, defaultValue: T[K] = undefined, nullishCoalesce = false) {
+    if (nullishCoalesce) {
+      return (obj && obj[prop]) ?? defaultValue;
+    } else {
+      return (obj && obj[prop]) || defaultValue;
+    }
   }
 
   protected normalizePattern(pattern: MsPattern): string {

packages/microservices/test/client/client-kafka.spec.ts

@@ -218,6 +218,20 @@ describe('ClientKafka', () => {
 
       expect(logCreatorSpy.called).to.be.true;
     });
+
+    it('should allow an empty postfixId', async () => {
+      const client = new ClientKafka({
+        postfixId: ''
+      });
+      expect(client.getClientId()).to.eq('nestjs-consumer');
+      expect(client.getGroupId()).to.eq('nestjs-group');
+    });
+
+    it('should postfix clientId and groupId with postfixId', async () => {
+      const client = new ClientKafka({});
+      expect(client.getClientId()).to.eq('nestjs-consumer-client');
+      expect(client.getGroupId()).to.eq('nestjs-group-client');
+    });
   });
 
   describe('subscribeToResponseOf', () => {