filter: Store reference to _sub instead of _stream_params.

In commit 4f6377d493 we added
`_stream_params` as a way of storing attributes such as stream name
and stream privacy, this involved adding a few calls within functions
that updated these values (in order to maintain consistency).

This commit replaces `_stream_params` with an always consistent `_sub`
object and removes unnecessary `_stream_params` related code. Once the
`_sub` object is available, calls to `stream_data` may be considered
suspicious as they can often be avoided by just picking the desired
attribute off of the `_sub` object.

static/js/filter.js

@@ -151,10 +151,12 @@ function message_matches_search_term(message, operator, operand) {
 function Filter(operators) {
     if (operators === undefined) {
         this._operators = [];
-        this._stream_params = undefined;
+        this._sub = undefined;
     } else {
         this._operators = this.fix_operators(operators);
-        this.fix_stream_params();
+        if (this.has_operator('stream')) {
+            this._sub = stream_data.get_sub_by_name(this.operands('stream')[0]);
+        }
     }
 }
 
@@ -480,7 +482,7 @@ Filter.prototype = {
         // this comes first because it has 3 term_types but is not a "complex filter"
         if (_.isEqual(term_types, ['stream', 'topic', 'search'])) {
             // if stream does not exist, redirect to All
-            if (!this._stream_params) {
+            if (!this._sub) {
                 return "#";
             }
             return  '/#narrow/stream/' + stream_data.name_to_slug(this.operands('stream')[0]) + '/topic/' + this.operands('topic')[0];
@@ -495,7 +497,7 @@ Filter.prototype = {
             switch (term_types[0]) {
             case 'stream':
                 // if stream does not exist, redirect to All
-                if (!this._stream_params) {
+                if (!this._sub) {
                     return "#";
                 }
                 return  '/#narrow/stream/' + stream_data.name_to_slug(this.operands('stream')[0]);
@@ -520,27 +522,6 @@ Filter.prototype = {
         return "#"; // redirect to All
     },
 
-    fix_stream_params: function () {
-        this._stream_params = this.get_stream_params();
-    },
-
-    get_stream_params: function () {
-        // we return undefined when we are unable to get these parameters
-        if (!this.has_operator('stream')) {
-            return;
-        }
-        const stream_name_from_search = this.operands('stream')[0];
-        const sub = stream_data.get_sub_by_name(stream_name_from_search);
-        if (!sub) {
-            return;
-        }
-        return {
-            _stream_name: sub.name,
-            _is_stream_private: sub.invite_only,
-            _is_web_public: sub.is_web_public,
-        };
-    },
-
     get_icon: function () {
         // We have special icons for the simple narrows available for the via sidebars.
         const term_types = this.sorted_term_types();
@@ -549,13 +530,13 @@ Filter.prototype = {
         case 'in-all':
             return 'home';
         case 'stream':
-            if (!this._stream_params) {
+            if (!this._sub) {
                 return 'question-circle-o';
             }
-            if (this._stream_params._is_stream_private) {
+            if (this._sub.invite_only) {
                 return 'lock';
             }
-            if (this._stream_params._is_web_public) {
+            if (this._sub.is_web_public) {
                 return 'globe';
             }
             return 'hashtag';
@@ -575,10 +556,10 @@ Filter.prototype = {
         const term_types = this.sorted_term_types();
         if (term_types.length === 3 && _.isEqual(term_types, ['stream', 'topic', 'search']) ||
             term_types.length === 2 && _.isEqual(term_types, ['stream', 'topic'])) {
-            if (!this._stream_params) {
+            if (!this._sub) {
                 return i18n.t('Unknown stream');
             }
-            return this._stream_params._stream_name;
+            return this._sub.name;
         }
         if (term_types.length === 1 || term_types.length === 2 && term_types[1] === 'search') {
             switch (term_types[0]) {
@@ -589,10 +570,10 @@ Filter.prototype = {
             case 'streams-public':
                 return i18n.t('Public stream messages in organization');
             case 'stream':
-                if (!this._stream_params) {
+                if (!this._sub) {
                     return i18n.t('Unknown stream');
                 }
-                return this._stream_params._stream_name;
+                return this._sub.name;
             case 'is-starred':
                 return i18n.t('Starred messages');
             case 'is-mentioned':

static/js/subs.js

@@ -140,20 +140,9 @@ exports.update_stream_name = function (sub, new_name) {
         compose_state.stream_name(new_name);
     }
 
-    // Update navbar stream name if needed
+    // Update navbar if needed
     const filter = narrow_state.filter();
-    if (filter && filter.operands("stream")[0] === old_name) {
+    if (filter && filter._sub && filter._sub.stream_id === sub.stream_id) {
-        // This works, but it relies on `filter.fix_stream_params` masking
-        // some bad behaviour in the Filter object. In particular, the fact
-        // that the Filter object relies on the search box which doesn't
-        // rename the currently focused stream.
-        //
-        // This will likely be improved as we migrate to using search pills
-        // and then a stream ID based representation of the stream in Filter.
-
-        // update the stream_params stored in the filter object
-        filter.fix_stream_params();
-        // use these to update the navbar
         tab_bar.render_title_area();
     }
 };
@@ -171,7 +160,7 @@ exports.update_stream_description = function (sub, description, rendered_descrip
 
     // Update navbar if needed
     const filter = narrow_state.filter();
-    if (filter && filter.operands("stream")[0] === sub.name) {
+    if (filter && filter._sub && filter._sub.stream_id === sub.stream_id) {
         tab_bar.render_title_area();
     }
 };
@@ -189,12 +178,9 @@ exports.update_stream_privacy = function (sub, values) {
     stream_ui_updates.update_add_subscriptions_elements(sub);
     stream_list.redraw_stream_privacy(sub);
 
-    // Update navbar stream name if needed
+    // Update navbar if needed
     const filter = narrow_state.filter();
-    if (filter && filter.operands("stream")[0] === sub.name) {
+    if (filter && filter._sub && filter._sub.stream_id === sub.stream_id) {
-        // update the stream_params stored in the filter object
-        filter.fix_stream_params();
-        // use these to update the navbar
         tab_bar.render_title_area();
     }
 };

static/js/tab_bar.js

@@ -49,9 +49,8 @@ function make_tab_data(filter) {
 
 exports.colorize_tab_bar = function () {
     const filter = narrow_state.filter();
-    if (filter === undefined || !filter.has_operator('stream') || !filter._stream_params) {return;}
+    if (filter === undefined || !filter._sub) {return;}
-    const color_for_stream = stream_data.get_color(filter._stream_params._stream_name);
+    $("#tab_list .stream > .fa").css('color', filter._sub.color);
-    $("#tab_list .stream > .fa").css('color', color_for_stream);
 };
 
 function append_and_display_title_area(tab_bar_data) {