Before this change, the way to add messages had a lot
of ping-pong-ing between MessageList and MessageListData,
where first the data got triaged, but not actually
inserted into data structures, and then subsequent
calls would add the data and get filtered results.
Now we have a simple API for MessageListData.add_messages
that does all the data stuff up front. Having a fully
function MLD.add_messages not only makes the ML.add_messages
function about four lines shorter, it also sets us up
to easily build standalone MLD objects before making
the heavier ML objects.
Most of this was straightforward.
Most functions that were grabbed verbatim and whole from
the original class still have one-line wrappers.
Many functions are just-the-data versions of functions that
remain in MessageList: see add, append, prepend, remove as
examples. In a typical pattern the MessageList code becomes
super simple:
prepend: function MessageList_prepend(messages) {
var viewable_messages = this.data.prepend(messages);
this.view.prepend(viewable_messages);
},
Two large functions had some minor surgery:
triage_messages =
top half of add_messages +
API to pass three lists back
change_message_id =
original version +
two simple callbacks to list
For the function update_muting_and_rerender(), we continue
to early-exit if this.muting_enabled is false, and we copied
that same defensive check to the new function
named update_items_for_muting(), even though it's technically
hidden from that codepath by the caller.