added better error handling for missing action handlers

interactor.js

@@ -8,7 +8,10 @@ export class Interactor {
 
   constructor(initialReaction = new Reaction()) {
     this.#actions.listen((action) => {
-      this[`_handle${action.constructor.name}`](action);
+      let funcRef = `_handle${action.constructor.name}`;
+      if (!this[funcRef])
+        throw `${this.constructor.name} does not have a handler defined for the action "${action.constructor.name}". Create one by adding a function definition named "${funcRef}" in the ${this.constructor.name} class.`;
+      this[funcRef](action);
     });
     this._react(initialReaction);
   }