ExternType.fromJson constructor

ExternType.fromJson(Object? json_)

Returns a new instance from a JSON value. May throw if the value does not have the expected structure.

Implementation

factory ExternType.fromJson(Object? json_) {
  Object? json = json_;
  if (json is Map) {
    final rt = json['runtimeType'];
    if (rt is String) {
      json = (
        const [
          'MemoryType',
          'TableType',
          'GlobalType',
          'FunctionType',
          'TagType'
        ].indexOf(rt),
        json
      );
    } else {
      final MapEntry(:key, :value) = json.entries.first;
      json = (key is int ? key : int.parse(key! as String), value);
    }
  }
  return switch (json) {
    (0, final value) || [0, final value] => MemoryType.fromJson(value),
    (1, final value) || [1, final value] => TableType.fromJson(value),
    (2, final value) || [2, final value] => GlobalType.fromJson(value),
    (3, final value) || [3, final value] => FunctionType.fromJson(value),
    (4, final value) || [4, final value] => TagType.fromJson(value),
    _ => throw Exception('Invalid JSON $json_'),
  };
}