mirror of https://github.com/zulip/zulip.git
111 lines
4.7 KiB
Markdown
111 lines
4.7 KiB
Markdown
# Unread counts and the pointer
|
|
|
|
When you're using Zulip and you reload, or narrow to a stream, how
|
|
does Zulip decide where to place you?
|
|
|
|
Conceptually, Zulip takes you to the place where you left off
|
|
(e.g. the first unread message), not the most recent messages, to
|
|
facilitate reviewing all the discussions that happened while you were
|
|
away from your computer. The scroll position is then set to keep that
|
|
message in view and away from both the top and bottom of the visible
|
|
section of messages.
|
|
|
|
But there a lot of details around doing this right, and around
|
|
counting unread messages. Here's how Zulip currently decides which
|
|
message to select, along with some notes on improvements we'd like to
|
|
make to the model.
|
|
|
|
First a bit of terminology:
|
|
|
|
* "Narrowing" is the process of filtering to a particular subset of
|
|
the messages the user has access to.
|
|
|
|
* The blue cursor box (the "pointer") is around is called the
|
|
"selected" message. Zulip ensures that the currently selected
|
|
message is always in-view.
|
|
|
|
## Pointer logic
|
|
|
|
### Recipient bar: message you clicked
|
|
|
|
If you enter a narrow by clicking on a message group's *recipient bar*
|
|
(stream/topic or private message recipient list at the top of a group
|
|
of messages), Zulip will select the the message you clicked on. This
|
|
provides a nice user experience where you get to see the stuff near
|
|
what you clicked on, and in fact the message you clicked on stays at
|
|
exactly the same scroll position in the window after the narrowing as
|
|
it was at before.
|
|
|
|
### Search or sidebar click: unread/recent matching narrow
|
|
|
|
If you instead narrow by clicking on something in the left sidebar or
|
|
typing some terms into the search box, Zulip will instead selected on
|
|
the first unread message matching that narrow, or if there are none,
|
|
the most recent messages matching that narrow. This provides the nice
|
|
user experience of taking you to the start of the new stuff (with
|
|
enough messages you'ev seen before still in view at the top to provide
|
|
you with context), which is usually what you want. (When finding the
|
|
"first unread message", Zulip ignores unread messages in muted streams
|
|
or in muted topics within non-muted streams.)
|
|
|
|
### Unnarrow: previous sequence
|
|
|
|
When you unnarrow using e.g. the escape key, you will automatically be
|
|
taken to the same message that was selected in the home view before
|
|
you narrowed, unless in the narrow you read new messages, in which
|
|
case you will be jumped forward to the first unread and non-muted
|
|
message in the home view (or the bottom of the feed if there is
|
|
none). This makes for a nice experience reading threads via the home
|
|
view in sequence.
|
|
|
|
### New home view: "high watermark"
|
|
|
|
When you open a new browser window or tab to the home view (a.k.a. the
|
|
interleaved view you get if you visit `/`), Zulip will select the
|
|
furthest down that your cursor has ever reached in the home
|
|
view. Because of the logic around unnarrowing in the last bullet, this
|
|
is usually just before the first unread message in the home view, but
|
|
if you never go to the home view, or you leave messages unread on some
|
|
streams in your home view, this can lag.
|
|
|
|
We plan to change this to automatically advance the pointer in a way
|
|
similar to the unnarrow logic.
|
|
|
|
### Narrow in a new tab: closest to pointer
|
|
|
|
When you load a new browser tab or window to a narrowed view, Zulip
|
|
will select the message closest to your pointer, which is what you
|
|
would have got had you loaded the browser window to your home view and
|
|
then clicked on the nearest message matching your narrow (which might
|
|
have been offscreen).
|
|
|
|
We plan to change this to match the Search/sidebar behavior.
|
|
|
|
### Forced reload: state preservation
|
|
|
|
When the server forces a reload of a browser that's otherwise caught
|
|
up (which happens within 30 minutes when a new version of the server
|
|
is deployed, usually at a type when the user isn't looking at the
|
|
browser), Zulip will preserve the state -- what (if any) narrow the
|
|
user was in, the selected message, and even exact scroll position!
|
|
|
|
For more on the user experience philosophy guiding these decisions,
|
|
see [the architectural overview](architecture-overview.html).
|
|
|
|
## Unread count logic
|
|
|
|
How does Zulip decide whether a message has been read by the user?
|
|
The algorithm needs to correctly handle a range of ways people might
|
|
use the product. The algorithm is as follows:
|
|
|
|
* Any message which is selected or above a message which is selected
|
|
is marked as read. So messages are marked as read as you scroll
|
|
down the keyboard when the pointer passes over them.
|
|
|
|
* If the whitspace at the very bottom of the feed is in view, all
|
|
messages in view are marked as read.
|
|
|
|
These two simple rules, combined with the pointer logic above, end up
|
|
matching user expectations well for whether the product should treat
|
|
them as having read a set of messages (or not).
|