Dart useful methods for parsing Json/map to object

dart-parsing-helper.dart

bool whenNull(dynamic value) {
  return value == null;
}

bool whenNotNull(dynamic value) {
  return value != null;
}

bool whenNullMap(String key, value) {
  return value == null;
}

bool whenNotNullMap(String key, value) {
  return value != null;
}

double parseValue(dynamic value, [double defValue]) {
  if (value == null) {
    return defValue;
  }
  try {
    if (value is String) {
      return double.parse(value);
    } else if (value is double) {
      return value;
    } else if (value is num) {
      return value.toDouble();
    } else {
      return defValue;
    }
  } catch (ex) {
    return defValue;
  }
}

dynamic getSafeBool(Map<dynamic, dynamic> map, String key,
    {bool defValue = false}) {
  var value = getSafe(map, key);
  return value == "true" || value == 0;
}

dynamic getSafe(Map<dynamic, dynamic> map, String key,
    [dynamic defValue = null]) {
  var value = defValue;
  if (map != null && map.containsKey(key)) {
    value = map[key] ?? defValue;
  }
  return value;
}