Use clearer error message when publishing without first advertising

Author: christophebedard

lib/bridge.js

@@ -189,6 +189,11 @@ class Bridge extends EventEmitter {
     this._registerOpMap('publish', (command) => {
       debug(`Publish a topic named ${command.topic} with ${JSON.stringify(command.msg)}`);
 
+      if (!this._topicsPublished.has(command.topic)) {
+        let error = new Error(`The topic ${command.topic} does not exist`);
+        error.level = 'error';
+        throw error;
+      }
       let publisher = this._resourceProvider.getPublisherByTopicName(command.topic);
       if (publisher) {
         publisher.publish(command.msg);