-
Notifications
You must be signed in to change notification settings - Fork 22.5k
/
index.md
71 lines (52 loc) · 2.48 KB
/
index.md
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
---
title: "RTCDataChannel: bufferedAmount property"
short-title: bufferedAmount
slug: Web/API/RTCDataChannel/bufferedAmount
page-type: web-api-instance-property
browser-compat: api.RTCDataChannel.bufferedAmount
---
{{APIRef("WebRTC")}}
The read-only `RTCDataChannel` property
**`bufferedAmount`** returns the number of bytes of data
currently queued to be sent over the data channel. The queue may build up as a
result of calls to the {{domxref("RTCDataChannel.send", "send()")}} method. This only
includes data buffered by the user agent itself; it doesn't include any framing overhead
or buffering done by the operating system or network hardware.
The user agent may implement the process of actually sending data in any way it
chooses; this may be done periodically during the event loop or truly asynchronously. As
messages are actually sent, this value is reduced accordingly.
> [!NOTE]
> Closing the data channel doesn't reset this count, even though the user agent purges
> the queued messages. However, even after closing the channel, attempts to send
> messages continue to add to the `bufferedAmount` value, even though the
> messages are neither sent nor buffered.
Whenever this value decreases to fall to or below the value specified in the
{{domxref("RTCDataChannel.bufferedAmountLowThreshold", "bufferedAmountLowThreshold")}}
property, the user agent fires the {{DOMxRef("RTCDataChannel.bufferedamountlow_event", "bufferedamountlow")}} event. This event may
be used, for example, to implement code which queues more messages to be sent whenever
there's room to buffer them.
## Value
The number of bytes of data currently queued to be sent over the data channel but have
not yet been sent.
## Example
The snippet below includes a function which changes the contents of a block with the ID
"bufferSize" to a string indicating the number of bytes currently buffered on an
{{domxref("RTCDataChannel")}}.
```js
const dc = peerConnection.createDataChannel("File Transfer");
// …
function showBufferedAmount(channel) {
const el = document.getElementById("bufferSize");
el.innerText = `${channel.bufferedAmount} bytes`;
}
```
## Specifications
{{Specifications}}
## Browser compatibility
{{Compat}}
## See also
- [WebRTC](/en-US/docs/Web/API/WebRTC_API)
- [Using WebRTC data channels](/en-US/docs/Web/API/WebRTC_API/Using_data_channels)
- {{domxref("RTCDataChannel")}}
- {{domxref("RTCDataChannel.bufferedAmountLowThreshold")}}
- {{DOMxRef("RTCDataChannel.bufferedamountlow_event", "bufferedamountlow")}} event