off method

@override Future<void> off(String event, [ dynamic callback(dynamic)? ])

Removes callback from event, or every callback of this client when it is null. Only this client's own JS bridge is detached -- listeners that other code put on the same WPP event stay.

Implementation

@override
Future<void> off(String event, [Function(dynamic)? callback]) async {
  final handlers = _listeners[event];
  if (handlers == null) return;
  if (callback != null) {
    handlers.remove(callback);
  } else {
    handlers.clear();
  }
  if (handlers.isNotEmpty) return;

  _listeners.remove(event);
  controller?.removeJavaScriptHandler(handlerName: _handlerName(event));
  final e = jsonEncode(event);
  await evaluateJs(
    '''(function() {
      var l = window.__dragoListeners;
      if (!l || !l[$e]) return;
      if (window.WPP) window.WPP.off($e, l[$e]);
      delete l[$e];
    })();''',
    tryPromise: false,
  );
}