diff --git a/.eslintrc.json b/.eslintrc.json
index e7e85ec763..163e308f7e 100644
--- a/.eslintrc.json
+++ b/.eslintrc.json
@@ -107,6 +107,7 @@
         "admin_sections": false,
         "admin": false,
         "stream_data": false,
+        "topic_data": false,
         "list_util": false,
         "muting": false,
         "Dict": false,
diff --git a/frontend_tests/node_tests/message_store.js b/frontend_tests/node_tests/message_store.js
index 07097900ff..34260f32f6 100644
--- a/frontend_tests/node_tests/message_store.js
+++ b/frontend_tests/node_tests/message_store.js
@@ -1,7 +1,8 @@
 add_dependencies({
     people: 'js/people.js',
-    util: 'js/util.js',
     pm_conversations: 'js/pm_conversations.js',
+    topic_data: 'js/topic_data.js',
+    util: 'js/util.js',
 });
 
 var noop = function () {};
@@ -15,8 +16,8 @@ set_global('alert_words', {
     process_message: noop,
 });
 
-set_global('stream_data' , {
-    process_message_for_recent_topics: noop,
+set_global('topic_data' , {
+    process_message: noop,
 });
 
 set_global('recent_senders', {
diff --git a/frontend_tests/node_tests/search_suggestion.js b/frontend_tests/node_tests/search_suggestion.js
index 0a027dde11..83eb717d34 100644
--- a/frontend_tests/node_tests/search_suggestion.js
+++ b/frontend_tests/node_tests/search_suggestion.js
@@ -12,6 +12,7 @@ add_dependencies({
     typeahead_helper: 'js/typeahead_helper.js',
     people: 'js/people.js',
     stream_data: 'js/stream_data.js',
+    topic_data: 'js/topic_data.js',
     narrow_state: 'js/narrow_state.js',
 });
 
@@ -35,7 +36,7 @@ init();
 
 set_global('narrow', {});
 
-global.stream_data.populate_stream_topics_for_tests({});
+topic_data.populate_for_tests({});
 
 (function test_basic_get_suggestions() {
     var query = 'fred';
@@ -575,7 +576,7 @@ init();
     };
 
     var recent_data = {};
-    global.stream_data.populate_stream_topics_for_tests(recent_data);
+    topic_data.populate_for_tests(recent_data);
     suggestions = search.get_suggestions('te');
     expected = [
         "te",
@@ -592,7 +593,7 @@ init();
         {name: 'test'},
     ];
 
-    global.stream_data.populate_stream_topics_for_tests(recent_data);
+    topic_data.populate_for_tests(recent_data);
 
     suggestions = search.get_suggestions('te');
     expected = [
@@ -677,7 +678,7 @@ init();
         return;
     };
 
-    global.stream_data.populate_stream_topics_for_tests({});
+    topic_data.populate_for_tests({});
 
     var suggestions = search.get_suggestions(query);
 
@@ -697,7 +698,7 @@ init();
         return;
     };
 
-    global.stream_data.populate_stream_topics_for_tests({});
+    topic_data.populate_for_tests({});
 
     var query = 'stream:of';
     var suggestions = search.get_suggestions(query);
@@ -749,7 +750,7 @@ init();
     people.add(alice);
 
 
-    global.stream_data.populate_stream_topics_for_tests({
+    topic_data.populate_for_tests({
         office: [
             {name: 'team'},
             {name: 'ignore'},
@@ -881,7 +882,7 @@ init();
         return;
     };
 
-    global.stream_data.populate_stream_topics_for_tests({});
+    topic_data.populate_for_tests({});
 
     // test allowing spaces with quotes surrounding operand
     var query = 'stream:"dev he"';
diff --git a/frontend_tests/node_tests/stream_data.js b/frontend_tests/node_tests/stream_data.js
index 937652cb13..ddbf382f15 100644
--- a/frontend_tests/node_tests/stream_data.js
+++ b/frontend_tests/node_tests/stream_data.js
@@ -13,12 +13,14 @@ add_dependencies({
     narrow: 'js/narrow.js',
     hash_util: 'js/hash_util.js',
     hashchange: 'js/hashchange.js',
+    topic_data: 'js/topic_data.js',
     util: 'js/util.js',
 });
 
 set_global('blueslip', {});
 
 var stream_data = require('js/stream_data.js');
+
 var people = global.people;
 
 (function test_basics() {
@@ -240,7 +242,7 @@ var people = global.people;
     assert(!ok);
 }());
 
-(function test_process_message_for_recent_topics() {
+(function test_process_message() {
     var stream_id = 55;
 
     var rome = {
@@ -255,9 +257,9 @@ var people = global.people;
         timestamp: 101,
         subject: 'toPic1',
     };
-    stream_data.process_message_for_recent_topics(message);
+    topic_data.process_message(message);
 
-    var history = stream_data.get_recent_topic_names(rome.stream_id);
+    var history = topic_data.get_recent_names(rome.stream_id);
     assert.deepEqual(history, ['toPic1']);
 
     message = {
@@ -265,8 +267,8 @@ var people = global.people;
         timestamp: 102,
         subject: 'Topic1',
     };
-    stream_data.process_message_for_recent_topics(message);
-    history = stream_data.get_recent_topic_names(rome.stream_id);
+    topic_data.process_message(message);
+    history = topic_data.get_recent_names(rome.stream_id);
     assert.deepEqual(history, ['Topic1']);
 
     message = {
@@ -274,12 +276,12 @@ var people = global.people;
         timestamp: 103,
         subject: 'topic2',
     };
-    stream_data.process_message_for_recent_topics(message);
-    history = stream_data.get_recent_topic_names(rome.stream_id);
+    topic_data.process_message(message);
+    history = topic_data.get_recent_names(rome.stream_id);
     assert.deepEqual(history, ['topic2', 'Topic1']);
 
-    stream_data.process_message_for_recent_topics(message, true);
-    history = stream_data.get_recent_topic_names(rome.stream_id);
+    topic_data.process_message(message, true);
+    history = topic_data.get_recent_names(rome.stream_id);
     assert.deepEqual(history, ['Topic1']);
 }());
 
@@ -307,7 +309,7 @@ var people = global.people;
         timestamp: 108,
         subject: 'topic2',
     };
-    stream_data.process_message_for_recent_topics(message);
+    topic_data.process_message(message);
 
     assert(stream_data.is_active(sub));
 }());
diff --git a/frontend_tests/node_tests/stream_list.js b/frontend_tests/node_tests/stream_list.js
index ce1940710b..ac9afcf3d2 100644
--- a/frontend_tests/node_tests/stream_list.js
+++ b/frontend_tests/node_tests/stream_list.js
@@ -10,6 +10,7 @@ add_dependencies({
     stream_color: 'js/stream_color',
     stream_data: 'js/stream_data',
     stream_sort: 'js/stream_sort',
+    topic_data: 'js/topic_data',
     unread: 'js/unread',
     unread_ui: 'js/unread_ui',
     util: 'js/util',
diff --git a/frontend_tests/node_tests/topic_generator.js b/frontend_tests/node_tests/topic_generator.js
index 284c463c7a..13955ed9e4 100644
--- a/frontend_tests/node_tests/topic_generator.js
+++ b/frontend_tests/node_tests/topic_generator.js
@@ -2,6 +2,7 @@ add_dependencies({
     muting: 'js/muting',
     stream_data: 'js/stream_data',
     stream_sort: 'js/stream_sort',
+    topic_data: 'js/topic_data',
     unread: 'js/unread',
 });
 
@@ -182,7 +183,7 @@ function is_odd(i) { return i % 2 === 1; }
         devel: devel_stream_id,
     };
 
-    global.stream_data.get_recent_topic_names = function (stream_id) {
+    topic_data.get_recent_names = function (stream_id) {
         switch (stream_id) {
             case muted_stream_id:
                 return ['red herring'];
diff --git a/frontend_tests/node_tests/topic_list.js b/frontend_tests/node_tests/topic_list.js
index d9bc58f89b..84ef81139c 100644
--- a/frontend_tests/node_tests/topic_list.js
+++ b/frontend_tests/node_tests/topic_list.js
@@ -5,6 +5,7 @@ add_dependencies({
     muting: 'js/muting',
     narrow: 'js/narrow',
     stream_data: 'js/stream_data',
+    topic_data: 'js/topic_data',
     templates: 'js/templates',
 });
 
@@ -27,7 +28,7 @@ global.compile_template('topic_list_item');
     recent_topics[stream_id] = [
         {name: "coding"},
     ];
-    global.stream_data.populate_stream_topics_for_tests(recent_topics);
+    topic_data.populate_for_tests(recent_topics);
     global.unread.num_unread_for_subject = function () {
         return 1;
     };
diff --git a/static/js/echo.js b/static/js/echo.js
index a04227b19e..b1267e2985 100644
--- a/static/js/echo.js
+++ b/static/js/echo.js
@@ -152,9 +152,9 @@ exports.try_deliver_locally = function try_deliver_locally(message_request) {
 exports.edit_locally = function edit_locally(message, raw_content, new_topic) {
     message.raw_content = raw_content;
     if (new_topic !== undefined) {
-        stream_data.process_message_for_recent_topics(message, true);
+        topic_data.process_message(message, true);
         message.subject = new_topic;
-        stream_data.process_message_for_recent_topics(message);
+        topic_data.process_message(message);
     }
 
     markdown.apply_markdown(message);
diff --git a/static/js/message_events.js b/static/js/message_events.js
index b8d8706769..7fbc099601 100644
--- a/static/js/message_events.js
+++ b/static/js/message_events.js
@@ -186,7 +186,7 @@ exports.update_messages = function update_messages(events) {
 
                 // Remove the recent topics entry for the old topics;
                 // must be called before we update msg.subject
-                stream_data.process_message_for_recent_topics(msg, true);
+                topic_data.process_message(msg, true);
                 // Update the unread counts; again, this must be called
                 // before we update msg.subject
                 unread.update_unread_topics(msg, event);
@@ -196,7 +196,7 @@ exports.update_messages = function update_messages(events) {
                 message_store.set_topic_edit_properties(msg);
                 // Add the recent topics entry for the new topics; must
                 // be called after we update msg.subject
-                stream_data.process_message_for_recent_topics(msg);
+                topic_data.process_message(msg);
             });
         }
 
diff --git a/static/js/message_store.js b/static/js/message_store.js
index 95478f7332..4951d0c788 100644
--- a/static/js/message_store.js
+++ b/static/js/message_store.js
@@ -150,7 +150,7 @@ exports.add_message_metadata = function (message) {
         composebox_typeahead.add_topic(message.stream, message.subject);
         message.reply_to = message.sender_email;
 
-        stream_data.process_message_for_recent_topics(message);
+        topic_data.process_message(message);
         exports.set_topic_edit_properties(message);
 
         recent_senders.process_message_for_senders(message);
diff --git a/static/js/search_suggestion.js b/static/js/search_suggestion.js
index 12225dbd39..7d4107d102 100644
--- a/static/js/search_suggestion.js
+++ b/static/js/search_suggestion.js
@@ -317,7 +317,7 @@ function get_topic_suggestions(last, operators) {
         return [];
     }
 
-    var topics = stream_data.get_recent_topic_names(stream_id);
+    var topics = topic_data.get_recent_names(stream_id);
 
     if (!topics || !topics.length) {
         return [];
diff --git a/static/js/stream_data.js b/static/js/stream_data.js
index efd568ff1c..c93cb9fb86 100644
--- a/static/js/stream_data.js
+++ b/static/js/stream_data.js
@@ -7,7 +7,6 @@ var exports = {};
 // Call clear_subscriptions() to initialize it.
 var stream_info;
 var subs_by_stream_id;
-var recent_topics = new Dict(); // stream_id -> array of objects
 
 var stream_ids_by_name = new Dict({fold_case: true});
 
@@ -21,7 +20,7 @@ exports.clear_subscriptions = function () {
 exports.clear_subscriptions();
 
 exports.is_active = function (sub) {
-    return recent_topics.has(sub.stream_id) || sub.newly_subscribed;
+    return topic_data.stream_has_topics(sub.stream_id) || sub.newly_subscribed;
 };
 
 exports.rename_sub = function (sub, new_name) {
@@ -380,44 +379,6 @@ exports.receives_audible_notifications = function (stream_name) {
     return sub.audible_notifications;
 };
 
-exports.process_message_for_recent_topics = function process_message_for_recent_topics(
-                                                message, remove_message) {
-    var current_timestamp = 0;
-    var count = 0;
-    var stream_id = message.stream_id;
-    var canon_topic = message.subject.toLowerCase();
-
-    var recents = recent_topics.get(stream_id) || [];
-
-    recents = _.filter(recents, function (item) {
-        var is_duplicate = (
-            item.name.toLowerCase() === canon_topic);
-        if (is_duplicate) {
-            current_timestamp = item.timestamp;
-            count = item.count;
-        }
-        return !is_duplicate;
-    });
-
-    if (remove_message !== undefined) {
-        count = count - 1;
-    } else {
-        count = count + 1;
-    }
-
-    if (count !== 0) {
-        recents.push({name: message.subject,
-                      count: count,
-                      timestamp: Math.max(message.timestamp, current_timestamp)});
-    }
-
-    recents.sort(function (a, b) {
-        return b.timestamp - a.timestamp;
-    });
-
-    recent_topics.set(stream_id, recents);
-};
-
 exports.get_streams_for_settings_page = function () {
     // Build up our list of subscribed streams from the data we already have.
     var subscribed_rows = exports.subscribed_subs();
@@ -472,23 +433,6 @@ exports.initialize_from_page_params = function () {
     delete page_params.never_subscribed;
 };
 
-exports.get_recent_topic_names = function (stream_id) {
-    var topic_objs = recent_topics.get(stream_id);
-
-    if (!topic_objs) {
-        return [];
-    }
-
-    return _.map(topic_objs, function (obj) {
-        return obj.name;
-    });
-};
-
-exports.populate_stream_topics_for_tests = function (stream_map) {
-    // This is only used by tests.
-    recent_topics = Dict.from(stream_map);
-};
-
 exports.get_newbie_stream = function () {
     // This is the stream that we narrow folks to after the tutorial.
 
diff --git a/static/js/topic_data.js b/static/js/topic_data.js
new file mode 100644
index 0000000000..5b4e2286d7
--- /dev/null
+++ b/static/js/topic_data.js
@@ -0,0 +1,70 @@
+var topic_data = (function () {
+
+var exports = {};
+
+var recent_topics = new Dict(); // stream_id -> array of objects
+
+exports.stream_has_topics = function (stream_id) {
+    return recent_topics.has(stream_id);
+};
+
+exports.process_message = function (message, remove_message) {
+    var current_timestamp = 0;
+    var count = 0;
+    var stream_id = message.stream_id;
+    var canon_topic = message.subject.toLowerCase();
+
+    var recents = recent_topics.get(stream_id) || [];
+
+    recents = _.filter(recents, function (item) {
+        var is_duplicate = (
+            item.name.toLowerCase() === canon_topic);
+        if (is_duplicate) {
+            current_timestamp = item.timestamp;
+            count = item.count;
+        }
+        return !is_duplicate;
+    });
+
+    if (remove_message !== undefined) {
+        count = count - 1;
+    } else {
+        count = count + 1;
+    }
+
+    if (count !== 0) {
+        recents.push({name: message.subject,
+                      count: count,
+                      timestamp: Math.max(message.timestamp, current_timestamp)});
+    }
+
+    recents.sort(function (a, b) {
+        return b.timestamp - a.timestamp;
+    });
+
+    recent_topics.set(stream_id, recents);
+};
+
+exports.get_recent_names = function (stream_id) {
+    var topic_objs = recent_topics.get(stream_id);
+
+    if (!topic_objs) {
+        return [];
+    }
+
+    return _.map(topic_objs, function (obj) {
+        return obj.name;
+    });
+};
+
+exports.populate_for_tests = function (stream_map) {
+    // This is only used by tests.
+    recent_topics = Dict.from(stream_map);
+};
+
+return exports;
+
+}());
+if (typeof module !== 'undefined') {
+    module.exports = topic_data;
+}
diff --git a/static/js/topic_generator.js b/static/js/topic_generator.js
index e01748f0b4..fd099c3b66 100644
--- a/static/js/topic_generator.js
+++ b/static/js/topic_generator.js
@@ -164,7 +164,7 @@ exports.get_next_topic = function (curr_stream, curr_topic) {
 
     function get_unmuted_topics(stream_name) {
         var stream_id = stream_data.get_stream_id(stream_name);
-        var topics = stream_data.get_recent_topic_names(stream_id);
+        var topics = topic_data.get_recent_names(stream_id);
         topics = _.reject(topics, function (topic) {
             return muting.is_topic_muted(stream_name, topic);
         });
diff --git a/static/js/topic_list.js b/static/js/topic_list.js
index 332c4240d8..d721e91794 100644
--- a/static/js/topic_list.js
+++ b/static/js/topic_list.js
@@ -52,7 +52,7 @@ exports.build_widget = function (parent_elem, my_stream_id, active_topic, max_to
     var my_stream_name = stream_data.get_sub_by_id(my_stream_id).name;
 
     function build_list(active_topic, max_topics) {
-        var topic_names = stream_data.get_recent_topic_names(my_stream_id);
+        var topic_names = topic_data.get_recent_names(my_stream_id);
 
         if (active_topic) {
             active_topic = active_topic.toLowerCase();
diff --git a/tools/test-js-with-node b/tools/test-js-with-node
index 45a52406ec..546f058742 100755
--- a/tools/test-js-with-node
+++ b/tools/test-js-with-node
@@ -49,6 +49,7 @@ enforce_fully_covered = {
     'static/js/search_suggestion.js',
     'static/js/stream_events.js',
     'static/js/stream_sort.js',
+    'static/js/topic_data.js',
     'static/js/topic_generator.js',
     'static/js/typeahead_helper.js',
     'static/js/typing_data.js',
diff --git a/zproject/settings.py b/zproject/settings.py
index 52ad6c2b9f..2e58cebb70 100644
--- a/zproject/settings.py
+++ b/zproject/settings.py
@@ -875,6 +875,7 @@ JS_SPECS = {
             'js/compose.js',
             'js/stream_color.js',
             'js/stream_data.js',
+            'js/topic_data.js',
             'js/stream_muting.js',
             'js/stream_events.js',
             'js/stream_create.js',