Adding the possibility of not applying broadcast to specific connecti…

…ons (#757)

* Add broadcast stateless exclude

* adjust implementation

packages/server/src/Document.ts

@@ -248,10 +248,12 @@ export class Document extends Doc {
   /**
    * Broadcast stateless message to all connections
    */
-  public broadcastStateless(payload: string): void {
+  public broadcastStateless(payload: string, filter?: (conn: Connection) => boolean): void {
     this.callbacks.beforeBroadcastStateless(this, payload)
 
-    this.getConnections().forEach(connection => {
+    const connections = filter ? this.getConnections().filter(filter) : this.getConnections()
+
+    connections.forEach(connection => {
       connection.sendStateless(payload)
     })
   }