This commit updates the frontend to show or hide the "Unsubscribe"
button in subscribers list in stream settings as per the
can_remove_subscribers_group setting for the stream.
This will help us avoid some duplicate code when
we use input pills for stream-create.
See the long comment in set_up_handlers() for
more context.
We also rename:
submit_add_subscriber_form -> subscribe_new_users
Ideally set_up_handlers() would also extract the
concept of clearing the pills as soon as you either
hit enter or clicked on the Add button, but our
current paradigm for clearing pills when you edit
subscribers for an existing stream on the Subscribers
tab is that we wait for the server to acknowledge
the request. I believe this is a bit of a misfeature,
but I am punting on that change for now.
For our Subscribers tab we want to enclose our
add-subscriber widget in a form for now, and we
continue to do so, but now we have the form tag
getting created in the parent template, not the
child.
Here is why:
We want to re-use our add-subscriber widget in an
upcoming commit for when you create streams.
In our create-stream UI, there is already an outer
<form>...</form> section of the HTML for the entire
process of creating a stream.
HTML does not yet you nest forms, and even though
browsers just silently ignore an inner form, we won't
want to create semantically incorrect HTML.
Therefore, we want the child template not to have
the form tags around them.
It's possible that we don't really even want to
enclose the input-pill widget and Add button inside
a form for the Subscribers tab, but tweaking that
for now is too risky. (We don't really take advantage
of the form tag in any meaningful way, since we
don't directly submit form data to the server, and
we can't use a single submit handler for the Enter
key and Add button due to some magic in our input
pills.)
In 4792af5682 I reformatted the template in such a way
that the div was no longer empty, and therefore
the :empty pseudoclass was not properly applied to
show the placeholder.
In cases where an opening tag is so long that we stretch
it to 2+ lines of code, we should try to use block-style
formatting in the template code.
Unfortunately, we have lots of legacy code that violates
this concept, so this is a timid fix.
There are also legit use cases like textarea where we
probably need to keep the ugly template syntax for things
to render properly.
Sahil Batra
Steve Howell
m-e-l-u-h-a-n