This fixes two bugs:
* If a user is not subscribed to a default stream, he or she would not
be have the option to invite users to that default stream.
* The initial streams checked in the invite modal were the
non-invite-only streams the user was subscribed to, not their
default streams.
Fixes: #4209.
There are no modern browsers that do not have built in JSON parsing
abilities. We do not need $.parseJSON as it now just serves as a call
to JSON.parse.
Attr now returns “checked” instead of true and “” instead of false in
higher versions. This fixes those issues.
The attr(“data-*”) have also been covered to data() as well.
In a few cases the $.each was doing something imperatively that was
terser and easier to understand by using a different Underscore method,
so a few of these I rewrote.
Some code was using the fact that jQuery sets `this` in the callback to
be the item; I rewrote those to use an explicit parameter.
Some code was using $(some selector).each(callback). I converted these
to _.each($(some selector), callback).
One function, ui.process_condensing, was written to be a jQuery $.each
callback despite being in a totally different module from code using it.
I noticed this and updated the function's args.
(imported from commit bf5922a35f257c168cc09ec1d077415d6ef19a03)