Fix unacknowledged publishes being rejected in the OnPublish step

Previously, the OnPublish promise was rejected because we don't have a publication ID to return.
Now, the API was changed to allow 'null' as value so we can resolve the promise with a 'null' value
to indicated that we don't have an acknowledge.

src/generic/Publisher.ts

@@ -8,11 +8,11 @@ import { WampMessage } from '../types/Protocol';
 import { PendingMap } from '../util/map';
 
 export class Publication implements IPublication {
-  private onPublished = new Deferred<WampID>();
+  private onPublished = new Deferred<WampID | null>();
   private resolved = false;
   constructor(private requestID: WampID, expectAck: boolean) {
     if (!expectAck) {
-      this.onPublished.reject('acknowledge is not set, expecting no answer');
+      this.onPublished.resolve(null);
       this.resolved = true;
     }
   }
@@ -32,7 +32,7 @@ export class Publication implements IPublication {
     this.onPublished.resolve(publicationId);
   }
 
-  public OnPublished(): Promise<WampID> {
+  public OnPublished(): Promise<WampID | null> {
     return this.onPublished.promise;
   }
 }

src/types/Connection.ts

@@ -84,7 +84,7 @@ export interface ISubscription {
 }
 
 export interface IPublication {
-  OnPublished(): Promise<WampID>;
+  OnPublished(): Promise<WampID | null>;
 }
 
 export interface IConnection {