From b32a9444dde492cda448c0e5a485ae7e46e36387 Mon Sep 17 00:00:00 2001
From: Steve Howell <showell@zulipchat.com>
Date: Tue, 22 Aug 2017 12:20:00 -0400
Subject: [PATCH] js: Clean up how we track default stream names.

We continue to have page_params.realm_default_streams, but
now we do lookups on whether a stream is a default stream
by using a Dict indexed by stream_id.

We are also careful to update that during live updates.

This fixes a flaw that we weren't updating the list of realms
correctly for events that remove a default stream.
---
 frontend_tests/node_tests/dispatch.js |  8 +++++--
 static/js/server_events_dispatch.js   |  2 +-
 static/js/stream_data.js              | 30 +++++++++++++++++++++------
 3 files changed, 31 insertions(+), 9 deletions(-)

diff --git a/frontend_tests/node_tests/dispatch.js b/frontend_tests/node_tests/dispatch.js
index 7e0dc2f7ae..21e1886999 100644
--- a/frontend_tests/node_tests/dispatch.js
+++ b/frontend_tests/node_tests/dispatch.js
@@ -455,8 +455,12 @@ with_overrides(function (override) {
     // default_streams
     var event = event_fixtures.default_streams;
     override('settings_streams.update_default_streams_table', noop);
-    dispatch(event);
-    assert_same(page_params.realm_default_streams, event.default_streams);
+    global.with_stub(function (stub) {
+        override('stream_data.set_realm_default_streams', stub.f);
+        dispatch(event);
+        var args = stub.get_args('realm_default_streams');
+        assert_same(args.realm_default_streams, event.default_streams);
+    });
 
 });
 
diff --git a/static/js/server_events_dispatch.js b/static/js/server_events_dispatch.js
index b148b2eb1a..77d80fb677 100644
--- a/static/js/server_events_dispatch.js
+++ b/static/js/server_events_dispatch.js
@@ -11,7 +11,7 @@ exports.dispatch_normal_event = function dispatch_normal_event(event) {
         break;
 
     case 'default_streams':
-        page_params.realm_default_streams = event.default_streams;
+        stream_data.set_realm_default_streams(event.default_streams);
         settings_streams.update_default_streams_table();
         break;
 
diff --git a/static/js/stream_data.js b/static/js/stream_data.js
index f300bca3a7..74ee7f8288 100644
--- a/static/js/stream_data.js
+++ b/static/js/stream_data.js
@@ -10,8 +10,6 @@ var subs_by_stream_id;
 
 var stream_ids_by_name = new Dict({fold_case: true});
 
-var defaults = {};
-
 exports.clear_subscriptions = function () {
     stream_info = new Dict({fold_case: true});
     subs_by_stream_id = new Dict();
@@ -224,8 +222,29 @@ exports.get_invite_only = function (stream_name) {
     return sub.invite_only;
 };
 
+var default_stream_ids = new Dict();
+
+exports.set_realm_default_streams = function (realm_default_streams) {
+    page_params.realm_default_streams = realm_default_streams;
+    default_stream_ids.clear();
+
+    realm_default_streams.forEach(function (stream) {
+        default_stream_ids.set(stream.stream_id, true);
+    });
+};
+
 exports.get_default_status = function (stream_name) {
-    return defaults.hasOwnProperty(stream_name);
+    var stream_id = exports.get_stream_id(stream_name);
+
+    if (!stream_id) {
+        return false;
+    }
+
+    return default_stream_ids.has(stream_id);
+};
+
+exports.is_default_stream_id = function (stream_id) {
+    return default_stream_ids.has(stream_id);
 };
 
 exports.get_name = function (stream_name) {
@@ -423,9 +442,7 @@ exports.initialize_from_page_params = function () {
         });
     }
 
-    page_params.realm_default_streams.forEach(function (stream) {
-        defaults[stream.name] = true;
-    });
+    exports.set_realm_default_streams(page_params.realm_default_streams);
 
     populate_subscriptions(page_params.subscriptions, true);
     populate_subscriptions(page_params.unsubscribed, false);
@@ -466,6 +483,7 @@ exports.remove_default_stream = function (stream_id) {
             return stream.stream_id === stream_id;
         }
     );
+    default_stream_ids.del(stream_id);
 };
 
 return exports;