jsonField<T> function

dynamic jsonField<T>(dynamic json, List<String> field, { bool nullable = true, T? defaultValue, bool printUnknownException = false, })

Implementation

dynamic jsonField <T>(dynamic json, List<String> field, {bool nullable = true, T? defaultValue, bool printUnknownException = false}) {
  dynamic retval = json;
  try {
    for (String f in field){
      retval = retval [f];
      if (retval == null && nullable) {
        break;
      }
    }
    if (retval == null) {
      if (!nullable) {
        throw BodyException (type: BodyExceptionType.isNull, fieldName: field.join("-"));
      } else {
        return defaultValue;
      }
    } else {
      assert (retval is T);
    }

    return retval;
  } on BodyException {
    rethrow;
  } on AssertionError catch (_) {
    throw BodyException(
      type: BodyExceptionType.isNotType,
      fieldName: field.join ("-"),
      failedType: T,
      currentType: retval.runtimeType
    );
  } on NoSuchMethodError catch (_) {
    throw BodyException(
      type: BodyExceptionType.isNull,
      fieldName: field.join ("_"),
      failedType: T,
      currentType: retval.runtimeType
    );
  } catch (error, bt) {
    if (printUnknownException) {
      Completer ().completeError(error, bt);
    }
    throw BodyException(
      type: BodyExceptionType.undefined,
      fieldName: field.join ("_")
    );
  }
}