diff --git a/.eslintrc.json b/.eslintrc.json
index 3cd4207645..79e21a8b26 100644
--- a/.eslintrc.json
+++ b/.eslintrc.json
@@ -331,6 +331,7 @@
         // Updated regex expressions are currently being tested in casper
         // files and will decide about a potential future enforcement of this rule.
         "no-useless-escape": 0,
+        "space-unary-ops": 2,
         "no-whitespace-before-property": 2,
         "no-with": 2,
         "one-var": [ "error", "never" ],
diff --git a/frontend_tests/node_tests/compose.js b/frontend_tests/node_tests/compose.js
index ac0980a448..ff6c5c35c8 100644
--- a/frontend_tests/node_tests/compose.js
+++ b/frontend_tests/node_tests/compose.js
@@ -566,8 +566,8 @@ run_test('send_message', () => {
             stub_state.send_msg_called += 1;
         };
         echo.reify_message_id = function (local_id, message_id) {
-            assert.equal(typeof(local_id), 'number');
-            assert.equal(typeof(message_id), 'number');
+            assert.equal(typeof (local_id), 'number');
+            assert.equal(typeof (message_id), 'number');
             stub_state.reify_message_id_checked += 1;
         };
 
@@ -779,11 +779,11 @@ function verify_filedrop_payload(payload) {
     assert.equal(payload.maxfilesize, 512);
     assert.equal(payload.data.csrfmiddlewaretoken, 'fake-csrf-token');
     assert.deepEqual(payload.raw_droppable, ['text/uri-list', 'text/plain']);
-    assert.equal(typeof(payload.drop), 'function');
-    assert.equal(typeof(payload.progressUpdated), 'function');
-    assert.equal(typeof(payload.error), 'function');
-    assert.equal(typeof(payload.uploadFinished), 'function');
-    assert.equal(typeof(payload.rawDrop), 'function');
+    assert.equal(typeof (payload.drop), 'function');
+    assert.equal(typeof (payload.progressUpdated), 'function');
+    assert.equal(typeof (payload.error), 'function');
+    assert.equal(typeof (payload.uploadFinished), 'function');
+    assert.equal(typeof (payload.rawDrop), 'function');
 }
 
 function test_raw_file_drop(raw_drop_func) {
diff --git a/frontend_tests/node_tests/compose_pm_pill.js b/frontend_tests/node_tests/compose_pm_pill.js
index b19b77bd8b..47f6b97cb7 100644
--- a/frontend_tests/node_tests/compose_pm_pill.js
+++ b/frontend_tests/node_tests/compose_pm_pill.js
@@ -100,7 +100,7 @@ run_test('pills', () => {
             get_by_email_called = false;
             var res = handler(iago.email, pills.items());
             assert(get_by_email_called);
-            assert.equal(typeof(res), 'object');
+            assert.equal(typeof (res), 'object');
             assert.equal(res.user_id, iago.user_id);
             assert.equal(res.display_value, iago.full_name);
         }());
diff --git a/frontend_tests/node_tests/filter.js b/frontend_tests/node_tests/filter.js
index 9a83802cab..a9c7b8a329 100644
--- a/frontend_tests/node_tests/filter.js
+++ b/frontend_tests/node_tests/filter.js
@@ -78,8 +78,8 @@ run_test('basics', () => {
     filter = new Filter(operators);
 
     assert(filter.is_search());
-    assert(! filter.can_apply_locally());
-    assert(! filter.is_exactly('stream'));
+    assert(!filter.can_apply_locally());
+    assert(!filter.is_exactly('stream'));
 
     // If our only stream operator is negated, then for all intents and purposes,
     // we don't consider ourselves to have a stream operator, because we don't
diff --git a/frontend_tests/node_tests/settings_muting.js b/frontend_tests/node_tests/settings_muting.js
index d65a0d7c27..09d2625db4 100644
--- a/frontend_tests/node_tests/settings_muting.js
+++ b/frontend_tests/node_tests/settings_muting.js
@@ -18,7 +18,7 @@ run_test('settings', () => {
     settings_muting.set_up();
 
     var click_handler = $('body').get_on_handler('click', '.settings-unmute-topic');
-    assert.equal(typeof(click_handler), 'function');
+    assert.equal(typeof (click_handler), 'function');
 
     var event = {
         stopImmediatePropagation: noop,
diff --git a/frontend_tests/node_tests/settings_user_groups.js b/frontend_tests/node_tests/settings_user_groups.js
index c2211dcbc2..f1f4eb82d5 100644
--- a/frontend_tests/node_tests/settings_user_groups.js
+++ b/frontend_tests/node_tests/settings_user_groups.js
@@ -154,11 +154,11 @@ run_test('populate_user_groups', () => {
         assert(config.fixed);
         assert(config.dropup);
         assert(config.stopAdvance);
-        assert.equal(typeof(config.source), 'function');
-        assert.equal(typeof(config.highlighter), 'function');
-        assert.equal(typeof(config.matcher), 'function');
-        assert.equal(typeof(config.sorter), 'function');
-        assert.equal(typeof(config.updater), 'function');
+        assert.equal(typeof (config.source), 'function');
+        assert.equal(typeof (config.highlighter), 'function');
+        assert.equal(typeof (config.matcher), 'function');
+        assert.equal(typeof (config.sorter), 'function');
+        assert.equal(typeof (config.updater), 'function');
 
         (function test_highlighter() {
             var fake_person = $.create('fake-person');
@@ -210,10 +210,10 @@ run_test('populate_user_groups', () => {
                 saved_fade_out_called = true;
             };
             $(cancel_selector).css = function (data) {
-                if (typeof(data) === 'string') {
+                if (typeof (data) === 'string') {
                     assert.equal(data, 'display');
                 }
-                assert.equal(typeof(data), 'object');
+                assert.equal(typeof (data), 'object');
                 assert.equal(data.display, 'inline-block');
                 assert.equal(data.opacity, '0');
                 return $(cancel_selector);
@@ -222,10 +222,10 @@ run_test('populate_user_groups', () => {
                 cancel_fade_to_called = true;
             };
             $(instructions_selector).css = function (data) {
-                if (typeof(data) === 'string') {
+                if (typeof (data) === 'string') {
                     assert.equal(data, 'display');
                 }
-                assert.equal(typeof(data), 'object');
+                assert.equal(typeof (data), 'object');
                 assert.equal(data.display, 'block');
                 assert.equal(data.opacity, '0');
                 return $(instructions_selector);
@@ -258,7 +258,7 @@ run_test('populate_user_groups', () => {
                      'Expected user email to be of Alice or Iago here.');
     };
     pills.onPillCreate = function (handler) {
-        assert.equal(typeof(handler), 'function');
+        assert.equal(typeof (handler), 'function');
         handler();
     };
 
@@ -273,7 +273,7 @@ run_test('populate_user_groups', () => {
             get_by_email_called = false;
             var res = handler(bob.email, pills.items());
             assert(get_by_email_called);
-            assert.equal(typeof(res), 'object');
+            assert.equal(typeof (res), 'object');
             assert.equal(res.user_id, bob.user_id);
             assert.equal(res.display_value, bob.full_name);
         }());
@@ -298,9 +298,9 @@ run_test('populate_user_groups', () => {
     test_create_item(create_item_handler);
 
     // Tests for settings_user_groups.set_up workflow.
-    assert.equal(typeof($('.organization form.admin-user-group-form').get_on_handler("submit")), 'function');
-    assert.equal(typeof($('#user-groups').get_on_handler('click', '.delete')), 'function');
-    assert.equal(typeof($('#user-groups').get_on_handler('keypress', '.user-group h4 > span')), 'function');
+    assert.equal(typeof ($('.organization form.admin-user-group-form').get_on_handler("submit")), 'function');
+    assert.equal(typeof ($('#user-groups').get_on_handler('click', '.delete')), 'function');
+    assert.equal(typeof ($('#user-groups').get_on_handler('keypress', '.user-group h4 > span')), 'function');
 });
 run_test('with_external_user', () => {
 
@@ -392,8 +392,8 @@ run_test('with_external_user', () => {
         callback = one;
         empty_fn = two;
         pill_hover_called = true;
-        assert.equal(typeof(one), 'function');
-        assert.equal(typeof(two), 'function');
+        assert.equal(typeof (one), 'function');
+        assert.equal(typeof (two), 'function');
     };
 
     var exit_button = $.create('fake-pill-exit');
@@ -716,10 +716,10 @@ run_test('on_events', () => {
             cancel_fade_out_called = true;
         };
         $(saved_selector).css = function (data) {
-            if (typeof(data) === 'string') {
+            if (typeof (data) === 'string') {
                 assert.equal(data, 'display');
             }
-            assert.equal(typeof(data), 'object');
+            assert.equal(typeof (data), 'object');
             assert.equal(data.display, 'inline-block');
             assert.equal(data.opacity, '0');
             return $(saved_selector);
diff --git a/frontend_tests/zjsunit/zjquery.js b/frontend_tests/zjsunit/zjquery.js
index 561317f79d..93e97e82d7 100644
--- a/frontend_tests/zjsunit/zjquery.js
+++ b/frontend_tests/zjsunit/zjquery.js
@@ -18,7 +18,7 @@ exports.make_event_store = (selector) => {
     var child_on_functions = new Dict();
 
     function generic_event(event_name, arg) {
-        if (typeof(arg) === 'function') {
+        if (typeof (arg) === 'function') {
             on_functions.set(event_name, arg);
         } else {
             var handler = on_functions.get(event_name);
@@ -94,8 +94,8 @@ exports.make_event_store = (selector) => {
                 event_name = arguments[0];
                 sel = arguments[1];
                 handler = arguments[2];
-                assert.equal(typeof(sel), 'string', 'String selectors expected here.');
-                assert.equal(typeof(handler), 'function', 'An handler function expected here.');
+                assert.equal(typeof (sel), 'string', 'String selectors expected here.');
+                assert.equal(typeof (handler), 'function', 'An handler function expected here.');
                 var child_on = child_on_functions.setdefault(sel, new Dict());
                 funcs = child_on.setdefault(event_name, []);
                 funcs.push(handler);
diff --git a/static/js/archive.js b/static/js/archive.js
index 057fc18f76..4f1f74118e 100644
--- a/static/js/archive.js
+++ b/static/js/archive.js
@@ -84,7 +84,7 @@ exports.initialize = function () {
         if (prev_sender !== undefined) {
             var first_group_msg = $(this).find('.message_row').first();
             var message_sender = first_group_msg.find('.message_sender');
-            if (! message_sender.find('.inline_profile_picture').length) {
+            if (!message_sender.find('.inline_profile_picture').length) {
                 message_sender.replaceWith(prev_sender.clone());
             }
         }
diff --git a/static/js/compose.js b/static/js/compose.js
index 526e569753..bd51bd4ead 100644
--- a/static/js/compose.js
+++ b/static/js/compose.js
@@ -310,7 +310,7 @@ exports.finish = function () {
         return;
     }
 
-    if (! compose.validate()) {
+    if (!compose.validate()) {
         return false;
     }
 
diff --git a/static/js/compose_actions.js b/static/js/compose_actions.js
index 897f3c565b..55b63b4b26 100644
--- a/static/js/compose_actions.js
+++ b/static/js/compose_actions.js
@@ -31,7 +31,7 @@ function hide_box() {
 
 function get_focus_area(msg_type, opts) {
     // Set focus to "Topic" when narrowed to a stream+topic and "New topic" button clicked.
-    if (msg_type === 'stream' && opts.stream && ! opts.subject) {
+    if (msg_type === 'stream' && opts.stream && !opts.subject) {
         return 'subject';
     } else if ((msg_type === 'stream' && opts.stream)
                || (msg_type === 'private' && opts.private_message_recipient)) {
diff --git a/static/js/composebox_typeahead.js b/static/js/composebox_typeahead.js
index b313398f9b..f7cc32ff29 100644
--- a/static/js/composebox_typeahead.js
+++ b/static/js/composebox_typeahead.js
@@ -22,11 +22,11 @@ exports.add_topic = function (uc_stream, uc_topic) {
     var stream = uc_stream.toLowerCase();
     var topic = uc_topic.toLowerCase();
 
-    if (! seen_topics.has(stream)) {
+    if (!seen_topics.has(stream)) {
         seen_topics.set(stream, new Dict());
     }
     var topic_dict = seen_topics.get(stream);
-    if (! topic_dict.has(topic)) {
+    if (!topic_dict.has(topic)) {
         topic_dict.set(topic, uc_topic);
     }
 };
diff --git a/static/js/dict.js b/static/js/dict.js
index b7485f853b..efb5d2fe6f 100644
--- a/static/js/dict.js
+++ b/static/js/dict.js
@@ -41,7 +41,7 @@ Dict.from = function Dict_from(obj, opts) {
  * passed to the Dict constructor.
  */
 Dict.from_array = function Dict_from_array(xs, opts) {
-    if (! (xs instanceof Array)) {
+    if (!(xs instanceof Array)) {
         throw new TypeError("Argument is not an array");
     }
 
diff --git a/static/js/filter.js b/static/js/filter.js
index 7cbc1e6654..d5d614c8e3 100644
--- a/static/js/filter.js
+++ b/static/js/filter.js
@@ -471,7 +471,7 @@ Filter.prototype = {
     _build_predicate: function () {
         var operators = this._operators;
 
-        if (! this.can_apply_locally()) {
+        if (!this.can_apply_locally()) {
             return function () { return true; };
         }
 
diff --git a/static/js/message_fetch.js b/static/js/message_fetch.js
index d2ef245ab8..df02fe9a23 100644
--- a/static/js/message_fetch.js
+++ b/static/js/message_fetch.js
@@ -63,7 +63,7 @@ function get_messages_success(data, opts) {
         // don't bother processing the newly arrived messages.
         return;
     }
-    if (! data) {
+    if (!data) {
         // The server occasionally returns no data during a
         // restart.  Ignore those responses and try again
         setTimeout(function () {
diff --git a/static/js/message_list_view.js b/static/js/message_list_view.js
index 7630dca589..49dd61fe30 100644
--- a/static/js/message_list_view.js
+++ b/static/js/message_list_view.js
@@ -791,7 +791,7 @@ MessageListView.prototype = {
         //   of the bottom of the currently rendered window and the
         //   bottom of the window does not abut the end of the
         //   message list
-        if (! (((selected_idx - this._render_win_start < this._RENDER_THRESHOLD)
+        if (!(((selected_idx - this._render_win_start < this._RENDER_THRESHOLD)
                 && (this._render_win_start !== 0)) ||
                ((this._render_win_end - selected_idx <= this._RENDER_THRESHOLD)
                 && (this._render_win_end !== this.list.num_items())))) {
diff --git a/static/js/message_scroll.js b/static/js/message_scroll.js
index cbb45fc01d..8fea209c53 100644
--- a/static/js/message_scroll.js
+++ b/static/js/message_scroll.js
@@ -6,7 +6,7 @@ var actively_scrolling = false;
 
 var loading_more_messages_indicator_showing = false;
 exports.show_loading_older = function () {
-    if (! loading_more_messages_indicator_showing) {
+    if (!loading_more_messages_indicator_showing) {
         loading.make_indicator($('#loading_more_messages_indicator'),
                                {abs_positioned: true});
         loading_more_messages_indicator_showing = true;
diff --git a/static/js/narrow.js b/static/js/narrow.js
index fe87a4ee5c..c9021ca9c3 100644
--- a/static/js/narrow.js
+++ b/static/js/narrow.js
@@ -177,7 +177,7 @@ exports.activate = function (raw_operators, opts) {
     var msg_list = new message_list.MessageList({
         data: msg_data,
         table_name: 'zfilt',
-        collapse_messages: ! narrow_state.get_current_filter().is_search(),
+        collapse_messages: !narrow_state.get_current_filter().is_search(),
     });
 
     msg_list.start_time = start_time;
diff --git a/static/js/pm_list.js b/static/js/pm_list.js
index 63be6c1c4b..42b1a591d9 100644
--- a/static/js/pm_list.js
+++ b/static/js/pm_list.js
@@ -154,7 +154,7 @@ exports.rebuild_recent = function (active_conversation) {
 exports.update_private_messages = function () {
     exports._build_private_messages_list();
 
-    if (! narrow_state.active()) {
+    if (!narrow_state.active()) {
         return;
     }
 
diff --git a/static/js/rows.js b/static/js/rows.js
index 3def66b8e6..3193273b37 100644
--- a/static/js/rows.js
+++ b/static/js/rows.js
@@ -55,7 +55,7 @@ var valid_table_names = {
 };
 
 exports.get_table = function (table_name) {
-    if (! valid_table_names.hasOwnProperty(table_name)) {
+    if (!valid_table_names.hasOwnProperty(table_name)) {
         return $();
     }
 
diff --git a/static/js/socket.js b/static/js/socket.js
index 025169fbd3..fc184f75d2 100644
--- a/static/js/socket.js
+++ b/static/js/socket.js
@@ -77,7 +77,7 @@ Socket.prototype = {
         request.error = error;
         this._save_request(request);
 
-        if (! this._can_send()) {
+        if (!this._can_send()) {
             this._try_to_reconnect({reason: 'cant_send'});
             return;
         }
diff --git a/static/js/stream_edit.js b/static/js/stream_edit.js
index 09dda83b4b..8fecf7c3dc 100644
--- a/static/js/stream_edit.js
+++ b/static/js/stream_edit.js
@@ -398,19 +398,19 @@ function change_stream_privacy(e) {
 
 function stream_desktop_notifications_clicked(e) {
     var sub = get_sub_for_target(e.target);
-    sub.desktop_notifications = ! sub.desktop_notifications;
+    sub.desktop_notifications = !sub.desktop_notifications;
     exports.set_stream_property(sub, 'desktop_notifications', sub.desktop_notifications);
 }
 
 function stream_audible_notifications_clicked(e) {
     var sub = get_sub_for_target(e.target);
-    sub.audible_notifications = ! sub.audible_notifications;
+    sub.audible_notifications = !sub.audible_notifications;
     exports.set_stream_property(sub, 'audible_notifications', sub.audible_notifications);
 }
 
 function stream_push_notifications_clicked(e) {
     var sub = get_sub_for_target(e.target);
-    sub.push_notifications = ! sub.push_notifications;
+    sub.push_notifications = !sub.push_notifications;
     exports.set_stream_property(sub, 'push_notifications', sub.push_notifications);
 }
 
diff --git a/static/js/stream_list.js b/static/js/stream_list.js
index a5852bd81c..064375aa83 100644
--- a/static/js/stream_list.js
+++ b/static/js/stream_list.js
@@ -305,7 +305,7 @@ exports.update_streams_sidebar = function () {
     exports.build_stream_list();
     exports.stream_cursor.redraw();
 
-    if (! narrow_state.active()) {
+    if (!narrow_state.active()) {
         return;
     }
 
diff --git a/static/js/stream_muting.js b/static/js/stream_muting.js
index 06675903f5..bb0729a8ff 100644
--- a/static/js/stream_muting.js
+++ b/static/js/stream_muting.js
@@ -43,7 +43,7 @@ exports.update_in_home_view = function (sub, value) {
         pointer.recenter_pointer_on_display = true;
         pointer.suppress_scroll_pointer_update = true;
 
-        if (! home_msg_list.empty()) {
+        if (!home_msg_list.empty()) {
             message_util.do_unread_count_updates(home_msg_list.all_messages());
         }
     }, 0);
diff --git a/static/js/stream_popover.js b/static/js/stream_popover.js
index c973475b44..95b3cfe792 100644
--- a/static/js/stream_popover.js
+++ b/static/js/stream_popover.js
@@ -77,7 +77,7 @@ function update_spectrum(popover, update_func) {
 
     var popover_root = popover.closest(".popover");
     var current_top_px = parseFloat(popover_root.css('top').replace('px', ''));
-    var height_delta = - (after_height - initial_height) * 0.5;
+    var height_delta = -(after_height - initial_height) * 0.5;
 
     popover_root.css('top', (current_top_px + height_delta) + "px");
 }
diff --git a/static/js/subs.js b/static/js/subs.js
index e7a31a110d..de511dd3e6 100644
--- a/static/js/subs.js
+++ b/static/js/subs.js
@@ -107,7 +107,7 @@ exports.active_stream = function () {
 };
 
 exports.toggle_home = function (sub) {
-    stream_muting.update_in_home_view(sub, ! sub.in_home_view);
+    stream_muting.update_in_home_view(sub, !sub.in_home_view);
     stream_edit.set_stream_property(sub, 'in_home_view', sub.in_home_view);
 };
 
@@ -829,7 +829,7 @@ exports.initialize = function () {
         // A hack.  Don't change the state of the checkbox if we
         // clicked on the checkbox itself.
         if (control[0] !== e.target) {
-            control.prop("checked", ! control.prop("checked"));
+            control.prop("checked", !control.prop("checked"));
         }
     });
 
diff --git a/static/js/tab_bar.js b/static/js/tab_bar.js
index af40746c2e..62992337b6 100644
--- a/static/js/tab_bar.js
+++ b/static/js/tab_bar.js
@@ -64,7 +64,7 @@ function make_tab_data() {
             if (filter.has_operator("pm-with")) {
                 var emails = filter.operands("pm-with")[0].split(',');
                 var names = _.map(emails, function (email) {
-                    if (! people.get_by_email(email)) {
+                    if (!people.get_by_email(email)) {
                         return email;
                     }
                     return people.get_by_email(email).full_name;
diff --git a/static/js/ui.js b/static/js/ui.js
index 84046e373c..465c20d883 100644
--- a/static/js/ui.js
+++ b/static/js/ui.js
@@ -52,7 +52,7 @@ function update_message_in_all_views(message_id, callback) {
 
 exports.show_error_for_unsupported_platform = function () {
     // Check if the user is using old desktop app
-    if (typeof(bridge) !== 'undefined') {
+    if (typeof (bridge) !== 'undefined') {
         // We don't internationalize this string because it is long,
         // and few users will have both the old desktop app and an
         // internationalized version of Zulip anyway.
diff --git a/static/js/unread_ops.js b/static/js/unread_ops.js
index b5ee214cdd..1283a5a07f 100644
--- a/static/js/unread_ops.js
+++ b/static/js/unread_ops.js
@@ -87,7 +87,7 @@ exports.notify_server_message_read = function (message, options) {
 // If we ever materially change the algorithm for this function, we
 // may need to update notifications.received_messages as well.
 exports.process_visible = function () {
-    if (! notifications.window_has_focus()) {
+    if (!notifications.window_has_focus()) {
         return;
     }