Helper class to wrap a StreamConsumer> and provide utility functions for writing to the StreamConsumer directly. The IOSink buffers the input given by all StringSink methods and will delay an addStream until the buffer is flushed.

When the IOSink is bound to a stream (through addStream) any call to the IOSink will throw a StateError. When the addStream completes, the IOSink will again be open for all calls.

If data is added to the IOSink after the sink is closed, the data will be ignored. Use the done future to be notified when the IOSink is closed.

Implemented by


done Future

Get a future that will complete when the consumer closes, or when an error occurs. This future is identical to the future returned by close.

encoding Encoding
read / write

The Encoding used when writing strings. Depending on the underlying consumer this property might be mutable.


IOSink(StreamConsumer<List<int>> target, {Encoding encoding: UTF8})


add(List<int> data) → void

Adds data to the target consumer, ignoring encoding.

addError(error, [StackTrace stackTrace]) → void

Passes the error to the target consumer as an error event.

addStream(Stream<List<int>> stream) → Future

Adds all elements of the given stream to this.

close() → Future

Close the target consumer.

flush() → Future

Returns a Future that completes once all buffered data is accepted by the to underlying StreamConsumer.

write(Object obj) → void

Converts obj to a String by invoking Object.toString and adds the encoding of the result to the target consumer.

writeAll(Iterable objects, [String separator = ""]) → void

Iterates over the given objects and writes them in sequence.

writeCharCode(int charCode) → void

Writes the charCode to this.

writeln([Object obj = ""]) → void

Converts obj to a String by invoking Object.toString and writes the result to this, followed by a newline.