diff --git a/webrtc/datachannel.nim b/webrtc/datachannel.nim
index e4061de..24fe8d2 100644
--- a/webrtc/datachannel.nim
+++ b/webrtc/datachannel.nim
@@ -65,7 +65,7 @@ proc ordered(t: DataChannelType): bool =
 # -- DataChannelStream --
 
 type
-  #TODO handle closing
+  DataChannelOnClose* = proc() {.raises: [], gcsafe.}
   DataChannelStream* = ref object
     id: uint16
     conn: SctpConn
@@ -73,8 +73,8 @@ type
     reliabilityParameter: uint32
     receivedData: AsyncQueue[seq[byte]]
     acked: bool
+    onClose: seq[DataChannelOnClose]
 
-  #TODO handle closing
   DataChannelConnection* = ref object
     readLoopFut: Future[void]
     streams: Table[uint16, DataChannelStream]
@@ -82,12 +82,15 @@ type
     conn*: SctpConn
     incomingStreams: AsyncQueue[DataChannelStream]
 
+proc addOnClose*(stream: DataChannelStream, onCloseProc: DataChannelOnClose) =
+  stream.onClose.add(onCloseProc)
+
 proc read*(
     stream: DataChannelStream
 ): Future[seq[byte]] {.async: (raises: [CancelledError]).} =
-  let x = await stream.receivedData.popFirst()
-  trace "read", length = x.len(), id = stream.id
-  return x
+  let data = await stream.receivedData.popFirst()
+  trace "read", length = data.len(), id = stream.id
+  return data
 
 proc write*(
     stream: DataChannelStream, buf: seq[byte]
@@ -99,7 +102,6 @@ proc write*(
 
   if stream.acked:
     sendInfo.unordered = not stream.reliability.ordered
-    #TODO add reliability params
 
   if buf.len == 0:
     trace "Datachannel write empty"
@@ -117,11 +119,13 @@ proc sendControlMessage(
       streamId: stream.id, endOfRecord: true, protocolId: uint32(WebRtcDcep)
     )
   trace "send control message", msg
-
   await stream.conn.write(encoded, sendInfo)
 
 proc closeStream*(stream: DataChannelStream) =
   stream.conn.closeChannel(stream.id)
+  for onCloseProc in stream.onClose:
+    onCloseProc()
+  stream.onClose = @[]
 
 proc openStream*(
     conn: DataChannelConnection,
@@ -152,7 +156,10 @@ proc openStream*(
     receivedData: newAsyncQueue[seq[byte]](),
   )
 
+  proc cleanup() =
+    conn.streams.del(streamId)
   conn.streams[streamId] = stream
+  stream.addOnClose(cleanup)
 
   let msg = DataChannelMessage(
     messageType: Open,
@@ -170,7 +177,6 @@ proc handleData(
   trace "handle data message", streamId, ppid = msg.params.protocolId, data = msg.data
 
   conn.streams.withValue(streamId, stream):
-    #TODO handle string vs binary
     if msg.params.protocolId in [uint32(WebRtcStringEmpty), uint32(WebRtcBinaryEmpty)]:
       # PPID indicate empty message
       await stream.receivedData.addLast(@[])
@@ -218,9 +224,7 @@ proc readLoop(conn: DataChannelConnection) {.async: (raises: [CancelledError]).}
   try:
     while true:
       let message = await conn.conn.read()
-      # TODO: check the protocolId
       if message.params.protocolId == uint32(WebRtcDcep):
-        #TODO should we really await?
         await conn.handleControl(message)
       else:
         await conn.handleData(message)