get method

dynamic get(dynamic field)

Gets a nested field by String or FieldPath from the snapshot.

Data can be accessed by providing a dot-notated path or FieldPath which recursively finds the specified data. If no data could be found at the specified path, a StateError will be thrown.

Implementation

dynamic get(dynamic field) {
  assert(field != null);
  assert(field is String || field is FieldPath,
      'Supported [field] types are [String] and [FieldPath]');

  if (!exists) {
    throw StateError(
        'cannot get a field on a $DocumentSnapshotPlatform which does not exist');
  }

  dynamic _findKeyValueInMap(String key, Map<String, dynamic> map) {
    if (map.containsKey(key)) {
      return map[key];
    }

    throw StateError(
        'field does not exist within the $DocumentSnapshotPlatform');
  }

  FieldPath fieldPath;
  if (field is String) {
    fieldPath = FieldPath.fromString(field);
  } else {
    fieldPath = field;
  }

  List<String> components = fieldPath.components;

  Map<String, dynamic>? snapshotData = data();

  dynamic _findComponent(int componentIndex, Map<String, dynamic>? data) {
    bool isLast = componentIndex + 1 == components.length;
    dynamic value = _findKeyValueInMap(components[componentIndex], data!);

    if (isLast) {
      return value;
    }

    if (value is Map) {
      return _findComponent(
          componentIndex + 1, Map<String, dynamic>.from(value));
    } else {
      throw StateError(
          'field does not exist within the $DocumentSnapshotPlatform');
    }
  }

  return _findComponent(0, snapshotData);
}