blob: 8bffc8ab93095d18027f27f6e7095c72d91d4822 [file] [log] [blame]
// Copyright (c) 2016, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
import 'dart:convert';
import 'package:async/async.dart';
import '../stream_channel.dart';
import 'stream_channel_transformer.dart';
/// A [StreamChannelTransformer] that transforms JSON documents—strings that
/// contain individual objects encoded as JSON—into decoded Dart objects.
/// This decodes JSON that's emitted by the transformed channel's stream, and
/// encodes objects so that JSON is passed to the transformed channel's sink.
/// If the transformed channel emits invalid JSON, this emits a
/// [FormatException]. If an unencodable object is added to the sink, it
/// synchronously throws a [JsonUnsupportedObjectError].
final StreamChannelTransformer<Object, String> jsonDocument =
const _JsonDocument();
class _JsonDocument implements StreamChannelTransformer<Object, String> {
const _JsonDocument();
StreamChannel<Object> bind(StreamChannel<String> channel) {
var stream =;
var sink = StreamSinkTransformer<Object, String>.fromHandlers(
handleData: (data, sink) {
return StreamChannel.withCloseGuarantee(stream, sink);