The code in unfade_messages() is O(N) over the number of
messages, but a simple flag allows us to track the fact that
all messages are unfaded, so we can short circuit the O(N)
logic in many cases.
A typical scenario now would be that you start typing a
stream while the topic is still empty. Modulo debouncing,
every keystroke now leads to a call to unfade_messages(),
but this change only does real work the first time.
(imported from commit da07cf408bbdbf5b381ff3ec33a5e05e34eef5b5)
The compose_fade has three public exports:
set_focused_recipient
unfade_messages
update_faded_messages
All code was pulled directly from compose.js, except for the
one-line setter of set_focused_recipient. The focused_recipients
variable that used to be in compose.js was moved to compose_fade.js,
hence the need for the setter.
(imported from commit 462ca5d0d0bd58612d0197f3734a8c78de8c6d30)
Steve Howell