hotkey: Add 'narrow to next unread followed topic' hotkey.

This commit adds a 'Shift + N' keyboard shortcut, which is
used to narrow to the next unread followed topic.

Fixes part of #27323.

help/include/reading-conversations.md

@@ -14,7 +14,8 @@
 
 !!! keyboard_tip ""
 
-    Use the <kbd>N</kbd> key to go to the next unread topic, or <kbd>P</kbd>
-    to go to the next unread direct message conversation.
+    Use the <kbd>N</kbd> key to go to the next unread topic, or <kbd>Shift</kbd> + <kbd>N</kbd>
+    for the next unread [followed](/help/follow-a-topic) topic, or <kbd>P</kbd> for the next
+    unread direct message conversation.
 
 {end_tabs}

help/keyboard-shortcuts.md

@@ -38,6 +38,8 @@ in the Zulip app to add more to your repertoire as needed.
 
 * **Next unread topic**: <kbd>N</kbd>
 
+* **Next unread followed topic**: <kbd>Shift</kbd> + <kbd>N</kbd>
+
 * **Next unread direct message**: <kbd>P</kbd>
 
 * **Search messages**: <kbd>/</kbd>

web/src/hotkey.js

@@ -88,6 +88,7 @@ const keydown_shift_mappings = {
     38: {name: "up_arrow", message_view_only: false}, // up arrow
     40: {name: "down_arrow", message_view_only: false}, // down arrow
     72: {name: "view_edit_history", message_view_only: true}, // 'H'
+    78: {name: "narrow_to_next_unread_followed_topic", message_view_only: false}, // 'N'
 };
 
 const keydown_unshift_mappings = {
@@ -904,7 +905,10 @@ export function process_hotkey(e, hotkey) {
             narrow.stream_cycle_forward();
             return true;
         case "n_key":
-            narrow.narrow_to_next_topic({trigger: "hotkey"});
+            narrow.narrow_to_next_topic({trigger: "hotkey", only_followed_topics: false});
+            return true;
+        case "narrow_to_next_unread_followed_topic":
+            narrow.narrow_to_next_topic({trigger: "hotkey", only_followed_topics: true});
             return true;
         case "p_key":
             narrow.narrow_to_next_pm_string({trigger: "hotkey"});

web/src/narrow.js

@@ -770,7 +770,11 @@ export function narrow_to_next_topic(opts = {}) {
         topic: narrow_state.topic(),
     };
 
-    const next_narrow = topic_generator.get_next_topic(curr_info.stream, curr_info.topic);
+    const next_narrow = topic_generator.get_next_topic(
+        curr_info.stream,
+        curr_info.topic,
+        opts.only_followed_topics,
+    );
 
     if (!next_narrow) {
         return;

web/src/topic_generator.js

@@ -49,7 +49,7 @@ export function next_topic(streams, get_topics, has_unread_messages, curr_stream
     return undefined;
 }
 
-export function get_next_topic(curr_stream, curr_topic) {
+export function get_next_topic(curr_stream, curr_topic, only_followed_topics) {
     let my_streams = stream_list_sort.get_streams();
 
     my_streams = my_streams.filter((stream_name) => {
@@ -71,11 +71,28 @@ export function get_next_topic(curr_stream, curr_topic) {
         return topics;
     }
 
+    function get_followed_topics(stream_name) {
+        const stream_id = stream_data.get_stream_id(stream_name);
+        let topics = stream_topic_history.get_recent_topic_names(stream_id);
+        topics = topics.filter((topic) => user_topics.is_topic_followed(stream_id, topic));
+        return topics;
+    }
+
     function has_unread_messages(stream_name, topic) {
         const stream_id = stream_data.get_stream_id(stream_name);
         return unread.topic_has_any_unread(stream_id, topic);
     }
 
+    if (only_followed_topics) {
+        return next_topic(
+            my_streams,
+            get_followed_topics,
+            has_unread_messages,
+            curr_stream,
+            curr_topic,
+        );
+    }
+
     return next_topic(my_streams, get_unmuted_topics, has_unread_messages, curr_stream, curr_topic);
 }
 

web/templates/keyboard_shortcuts.hbs

@@ -40,6 +40,10 @@
                     <td class="definition">{{t 'Next unread topic' }}</td>
                     <td><span class="hotkey"><kbd>N</kbd></span></td>
                 </tr>
+                <tr>
+                    <td class="definition">{{t 'Next unread followed topic' }}</td>
+                    <td><span class="hotkey"><kbd>Shift</kbd> + <kbd>N</kbd></span></td>
+                </tr>
                 <tr>
                     <td class="definition">{{t 'Next unread direct message' }}</td>
                     <td><span class="hotkey"><kbd>P</kbd></span></td>

web/tests/hotkey.test.js

@@ -182,6 +182,7 @@ run_test("mappings", () => {
     assert.equal(map_down(13).name, "enter");
     assert.equal(map_down(46).name, "delete");
     assert.equal(map_down(13, true).name, "enter");
+    assert.equal(map_down(78, true).name, "narrow_to_next_unread_followed_topic");
 
     assert.equal(map_press(47).name, "search"); // slash
     assert.equal(map_press(106).name, "vim_down"); // j
@@ -231,11 +232,15 @@ run_test("mappings", () => {
     navigator.platform = "";
 });
 
-function process(s) {
+function process(s, shiftKey, keydown = false) {
     const e = {
         which: s.codePointAt(0),
+        shiftKey,
     };
     try {
+        if (keydown) {
+            return hotkey.process_keydown(e);
+        }
         return hotkey.process_keypress(e);
     } catch (error) /* istanbul ignore next */ {
         // An exception will be thrown here if a different
@@ -247,9 +252,9 @@ function process(s) {
     }
 }
 
-function assert_mapping(c, module, func_name, shiftKey) {
+function assert_mapping(c, module, func_name, shiftKey, keydown) {
     stubbing(module, func_name, (stub) => {
-        assert.ok(process(c, shiftKey));
+        assert.ok(process(c, shiftKey, keydown));
         assert.equal(stub.num_calls, 1);
     });
 }
@@ -442,6 +447,10 @@ run_test("n/p keys", () => {
     assert_mapping("n", narrow, "narrow_to_next_topic");
 });
 
+run_test("narrow next unread followed topic", () => {
+    assert_mapping("N", narrow, "narrow_to_next_topic", true, true);
+});
+
 run_test("motion_keys", () => {
     const codes = {
         down_arrow: 40,

web/tests/topic_generator.test.js

@@ -89,9 +89,9 @@ run_test("topics", ({override}) => {
     override(stream_topic_history, "get_recent_topic_names", (stream_id) => {
         switch (stream_id) {
             case muted_stream_id:
-                return ["ms-topic1", "ms-topic2"];
+                return ["ms-topic1", "ms-topic2", "followed"];
             case devel_stream_id:
-                return ["muted", "python"];
+                return ["muted", "python", "followed"];
         }
 
         return [];
@@ -107,12 +107,26 @@ run_test("topics", ({override}) => {
 
     override(user_topics, "is_topic_muted", (_stream_name, topic) => topic === "muted");
 
+    override(user_topics, "is_topic_followed", (_stream_name, topic) => topic === "followed");
+
     let next_item = tg.get_next_topic("announce", "whatever");
     assert.deepEqual(next_item, {
         stream: "devel",
         topic: "python",
     });
 
+    next_item = tg.get_next_topic("devel", "python");
+    assert.deepEqual(next_item, {
+        stream: "devel",
+        topic: "followed",
+    });
+
+    next_item = tg.get_next_topic("muted", "whatever", true);
+    assert.deepEqual(next_item, {
+        stream: "muted",
+        topic: "followed",
+    });
+
     next_item = tg.get_next_topic("muted", undefined);
     assert.deepEqual(next_item, {
         stream: "muted",