isDestroyed() returns a boolean to let you know if the daily-js instance has had destroy() called on it. If the instance is destroyed, it can not be re-used.

You can re-use the daily-js call frame or call object multiple times (a sequence of join(), leave(), join(), etc method calls will work as expected).

But when you are finished with the daily-js call object, you should call destroy() to free all resources associated with it.

At this point, isDestroyed() will return true and the call instance is no longer considered valid and should not be used.

Starting in daily-js 0.43.0, using a call instance after calling destroy() on it will not be allowed and any attempt will throw an Error in order to help defend against this. If you believe you may be using destroyed instances and wish to preview this behavior, add strictMode: true to the properties passed in to your factory method.