From ab2e7e097a4cf0c8ca3bd73e9380b58b06f7030a Mon Sep 17 00:00:00 2001
From: YashRE42 <33805964+YashRE42@users.noreply.github.com>
Date: Tue, 16 Jun 2020 17:20:22 +0000
Subject: [PATCH] navbar: Switch make_tab_bar conditionals to using filter/sub
 values.

Previously, this function relied on the return value of
`filter.get_icon()` which made it brittle.
Directly using the properties of the filter and sub object makes this
more explicit about the intentions and robust.
---
 static/js/tab_bar.js | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/static/js/tab_bar.js b/static/js/tab_bar.js
index df8a87bdef..4a9782ab9e 100644
--- a/static/js/tab_bar.js
+++ b/static/js/tab_bar.js
@@ -25,13 +25,16 @@ function make_tab_data(filter) {
     }
     tab_data.title = filter.get_title();
     tab_data.icon = filter.get_icon();
-    if (tab_data.icon === 'question-circle-o') {
+    if (filter.has_operator('stream') && !filter._sub) {
         tab_data.sub_count = '0';
         tab_data.formatted_sub_count = '0';
         tab_data.rendered_narrow_description = i18n.t("This stream does not exist or is private.");
         return tab_data;
     }
-    if (['hashtag', 'lock', 'globe'].includes(tab_data.icon)) {
+    if (filter._sub) {
+        // We can now be certain that the narrow
+        // involves a stream which exists and
+        // the current user can access.
         const stream = filter.operands("stream")[0];
         // We can rely on current_stream because if the stream doesn't
         // exist then the "question-circle-o" case would case early exit.