changeConfig method
Implementation
Future<void> changeConfig(SeatingChartConfigChange configChange) async {
final String promiseId = DateTime.now().millisecondsSinceEpoch.toString();
final Completer<void> completer = Completer<void>();
_pendingPromises[promiseId] = completer;
final String jsArray = jsonEncode(configChange.toJson());
await _controller.evaluateJavascript('''
chart.changeConfig($jsArray)
.then(() => window.changeConfigJsChannel.postMessage(JSON.stringify({
"id": "$promiseId\",
\"status\": \"resolved\"
})))
.catch(error => window.changeConfigJsChannel.postMessage(JSON.stringify({
\"id\": \"$promiseId\",
\"status\": \"error\",
\"message\": error
})));
''');
return completer.future;
}