registering vr modules and dispatching messages

vr-module-register.ts

public registerModule(): Observable<IServiceMessage> {
      return this.asObservable().map((mod) => {
        if (!_.isNil(mod) &&
            !_.isNil(mod.id) &&
            !_.isNil(mod.name)) {
            this.store.dispatch( { type: VR_MODULE_ADDED, payload: mod });
            return <IServiceMessage> {
              id: '0000',
              content: `Registered vr module '${mod.name}'`
            };
          }
          return <IServiceMessage>{
            id: '000',
            content: mod ? `Could not register vr module '${mod.id}'` :
                           `Could not register unknown vr module`
          };
      });
    }