diff --git a/.eslintrc.json b/.eslintrc.json
index 9f6a6aeea0..11a6f93a17 100644
--- a/.eslintrc.json
+++ b/.eslintrc.json
@@ -17,6 +17,7 @@
     "rules": {
         "array-callback-return": "error",
         "array-bracket-spacing": "error",
+        "arrow-parens": "error",
         "arrow-spacing": [ "error", { "before": true, "after": true } ],
         "block-scoped-var": "error",
         "brace-style": [ "error", "1tbs", { "allowSingleLine": true } ],
diff --git a/frontend_tests/node_tests/activity.js b/frontend_tests/node_tests/activity.js
index d73f246386..013edf1ac5 100644
--- a/frontend_tests/node_tests/activity.js
+++ b/frontend_tests/node_tests/activity.js
@@ -18,7 +18,7 @@ const _document = {
 const _channel = {};
 
 const _ui = {
-    get_content_element: element => element,
+    get_content_element: (element) => element,
 };
 
 const _keydown_util = {
@@ -686,7 +686,7 @@ run_test('initialize', () => {
             func();
         },
     });
-    $(window).focus = func => func();
+    $(window).focus = (func) => func();
     $(window).idle = () => {};
 
     channel.post = function (payload) {
diff --git a/frontend_tests/node_tests/bot_data.js b/frontend_tests/node_tests/bot_data.js
index f5bd8b823b..df99d7b7cf 100644
--- a/frontend_tests/node_tests/bot_data.js
+++ b/frontend_tests/node_tests/bot_data.js
@@ -137,7 +137,7 @@ run_test('test_basics', () => {
         bot_data.add({...test_bot, user_id: 45, email: 'bot2@zulip.com', owner_id: me.user_id, is_active: true});
         bot_data.add({...test_bot, user_id: 46, email: 'bot3@zulip.com', owner_id: fred.user_id, is_active: true});
 
-        const editable_bots = bot_data.get_editable().map(bot => bot.email);
+        const editable_bots = bot_data.get_editable().map((bot) => bot.email);
         assert.deepEqual(['bot1@zulip.com', 'bot2@zulip.com'], editable_bots);
     }());
 
diff --git a/frontend_tests/node_tests/composebox_typeahead.js b/frontend_tests/node_tests/composebox_typeahead.js
index a433cc3bd8..179dab148f 100644
--- a/frontend_tests/node_tests/composebox_typeahead.js
+++ b/frontend_tests/node_tests/composebox_typeahead.js
@@ -114,7 +114,7 @@ const emojis_by_name = new Map(Object.entries({
     heart: emoji_heart,
     headphones: emoji_headphones,
 }));
-const emoji_list = Array.from(emojis_by_name.values(), emoji_dict => {
+const emoji_list = Array.from(emojis_by_name.values(), (emoji_dict) => {
     if (emoji_dict.is_realm_emoji === true) {
         return {
             emoji_name: emoji_dict.name,
@@ -518,7 +518,7 @@ run_test('content_typeahead_selected', () => {
 });
 
 function sorted_names_from(subs) {
-    return subs.map(sub => sub.name).sort();
+    return subs.map((sub) => sub.name).sort();
 }
 
 run_test('initialize', () => {
@@ -1320,7 +1320,7 @@ run_test('begins_typeahead', () => {
     assert_typeahead_equals("```test", "ing", false);
     assert_typeahead_equals("~~~test", "ing", false);
     const terminal_symbols = ',.;?!()[] "\'\n\t';
-    terminal_symbols.split().forEach(symbol => {
+    terminal_symbols.split().forEach((symbol) => {
         assert_stream_list("#test", symbol);
         assert_typeahead_equals("@test", symbol, all_mentions);
         assert_typeahead_equals(":test", symbol, emoji_list);
diff --git a/frontend_tests/node_tests/dispatch.js b/frontend_tests/node_tests/dispatch.js
index dacc3cee16..b9ba52c088 100644
--- a/frontend_tests/node_tests/dispatch.js
+++ b/frontend_tests/node_tests/dispatch.js
@@ -8,7 +8,7 @@ const test_user = events.test_user;
 
 set_global('$', global.make_zjquery());
 
-global.patch_builtin('setTimeout', func => func());
+global.patch_builtin('setTimeout', (func) => func());
 
 // These dependencies are closer to the dispatcher, and they
 // apply to all tests.
@@ -570,7 +570,7 @@ with_overrides(function (override) {
         override('subs.add_sub_to_table', noop);
         dispatch(event);
         const args = stub.get_args('streams');
-        assert_same(args.streams.map(stream => stream.stream_id), [42, 99]);
+        assert_same(args.streams.map((stream) => stream.stream_id), [42, 99]);
     });
 
     // stream delete
diff --git a/frontend_tests/node_tests/dropdown_list_widget.js b/frontend_tests/node_tests/dropdown_list_widget.js
index d3adb3352a..fc1a122d19 100644
--- a/frontend_tests/node_tests/dropdown_list_widget.js
+++ b/frontend_tests/node_tests/dropdown_list_widget.js
@@ -24,7 +24,7 @@ run_test('basic_functions', () => {
     let updated_value;
     const opts = {
         widget_name: 'my_setting',
-        data: ['one', 'two', 'three'].map(x => ({name: x, value: x})),
+        data: ['one', 'two', 'three'].map((x) => ({name: x, value: x})),
         value: 'one',
         on_update: (val) => { updated_value = val; },
         default_text: i18n.t("not set"),
@@ -55,7 +55,7 @@ run_test('basic_functions', () => {
 run_test('no_default_value', () => {
     const opts = {
         widget_name: 'my_setting',
-        data: ['one', 'two', 'three'].map(x => ({name: x, value: x})),
+        data: ['one', 'two', 'three'].map((x) => ({name: x, value: x})),
         default_text: i18n.t("not set"),
         render_text: (text) => `rendered: ${text}`,
         null_value: 'null-value',
diff --git a/frontend_tests/node_tests/filter.js b/frontend_tests/node_tests/filter.js
index 729a2ef84e..29d92e7523 100644
--- a/frontend_tests/node_tests/filter.js
+++ b/frontend_tests/node_tests/filter.js
@@ -35,7 +35,7 @@ people.add_active_user(steve);
 people.initialize_current_user(me.user_id);
 
 function assert_same_operators(result, terms) {
-    terms = terms.map(term => {
+    terms = terms.map((term) => {
         // If negated flag is undefined, we explicitly
         // set it to false.
         let negated = term.negated;
@@ -571,7 +571,7 @@ run_test('canonicalizations', () => {
 });
 
 function get_predicate(operators) {
-    operators = operators.map(op => ({
+    operators = operators.map((op) => ({
         operator: op[0],
         operand: op[1],
     }));
@@ -1558,7 +1558,7 @@ run_test('navbar_helpers', () => {
         },
     ];
 
-    test_cases.forEach(test_case => {
+    test_cases.forEach((test_case) => {
         test_helpers(test_case);
     });
 
@@ -1579,7 +1579,7 @@ run_test('navbar_helpers', () => {
         },
     ];
 
-    redirect_edge_cases.forEach(test_case => {
+    redirect_edge_cases.forEach((test_case) => {
         test_redirect_url_with_search(test_case);
     });
 
diff --git a/frontend_tests/node_tests/message_fetch.js b/frontend_tests/node_tests/message_fetch.js
index f4e62f81aa..6d1a32ca58 100644
--- a/frontend_tests/node_tests/message_fetch.js
+++ b/frontend_tests/node_tests/message_fetch.js
@@ -107,7 +107,7 @@ function config_process_results(messages) {
         messages_processed_for_bools.push(message);
     };
 
-    message_store.add_message_metadata = message => message;
+    message_store.add_message_metadata = (message) => message;
 
     message_util.do_unread_count_updates = function (arg) {
         assert.deepEqual(arg, messages);
@@ -130,7 +130,7 @@ function config_process_results(messages) {
 }
 
 function message_range(start, end) {
-    return _.range(start, end).map(idx => ({
+    return _.range(start, end).map((idx) => ({
         id: idx,
     }));
 }
diff --git a/frontend_tests/node_tests/message_list_data.js b/frontend_tests/node_tests/message_list_data.js
index 23e6055f2e..a5aa70fa7d 100644
--- a/frontend_tests/node_tests/message_list_data.js
+++ b/frontend_tests/node_tests/message_list_data.js
@@ -155,12 +155,12 @@ run_test('more muting', () => {
     });
 
     assert.deepEqual(
-        mld._all_items.map(message => message.id),
+        mld._all_items.map((message) => message.id),
         [3, 4, 7, 8]
     );
 
     assert.deepEqual(
-        mld.all_messages().map(message => message.id),
+        mld.all_messages().map((message) => message.id),
         [4, 8]
     );
 
@@ -177,12 +177,12 @@ run_test('more muting', () => {
     const more_info = mld.add_messages(more_messages);
 
     assert.deepEqual(
-        mld._all_items.map(message => message.id),
+        mld._all_items.map((message) => message.id),
         [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
     );
 
     assert.deepEqual(
-        mld.all_messages().map(message => message.id),
+        mld.all_messages().map((message) => message.id),
         [2, 4, 6, 8, 10]
     );
 
diff --git a/frontend_tests/node_tests/message_list_view.js b/frontend_tests/node_tests/message_list_view.js
index c0fd49b3d1..6c6eb34fbd 100644
--- a/frontend_tests/node_tests/message_list_view.js
+++ b/frontend_tests/node_tests/message_list_view.js
@@ -169,7 +169,7 @@ run_test('merge_message_groups', () => {
     }
 
     function extract_message_ids(lst) {
-        return lst.map(item => item.msg.id);
+        return lst.map((item) => item.msg.id);
     }
 
     function assert_message_list_equal(list1, list2) {
@@ -546,7 +546,7 @@ run_test('render_windows', () => {
     let messages;
 
     function reset_list(opts) {
-        messages = _.range(opts.count).map(i => ({
+        messages = _.range(opts.count).map((i) => ({
             id: i,
         }));
         list.selected_idx = function () { return 0; };
diff --git a/frontend_tests/node_tests/message_store.js b/frontend_tests/node_tests/message_store.js
index ab1a72fc1b..a6029a6b4c 100644
--- a/frontend_tests/node_tests/message_store.js
+++ b/frontend_tests/node_tests/message_store.js
@@ -65,7 +65,7 @@ people.initialize_current_user(me.user_id);
 
 function convert_recipients(people) {
     // Display_recipient uses `id` for user_ids.
-    return people.map(p => ({
+    return people.map((p) => ({
         email: p.email,
         id: p.user_id,
         full_name: p.full_name,
diff --git a/frontend_tests/node_tests/narrow.js b/frontend_tests/node_tests/narrow.js
index 1a8e81afd0..fdf4803902 100644
--- a/frontend_tests/node_tests/narrow.js
+++ b/frontend_tests/node_tests/narrow.js
@@ -17,7 +17,7 @@ set_global('resize', {
 zrequire('narrow');
 
 function set_filter(operators) {
-    operators = operators.map(op => ({
+    operators = operators.map((op) => ({
         operator: op[0],
         operand: op[1],
     }));
diff --git a/frontend_tests/node_tests/narrow_local.js b/frontend_tests/node_tests/narrow_local.js
index 35eeedc7f4..c984d5cc76 100644
--- a/frontend_tests/node_tests/narrow_local.js
+++ b/frontend_tests/node_tests/narrow_local.js
@@ -68,7 +68,7 @@ function test_with(fixture) {
     assert.deepEqual(id_info, fixture.expected_id_info);
 
     const msgs = msg_data.all_messages();
-    const msg_ids = msgs.map(message => message.id);
+    const msg_ids = msgs.map((message) => message.id);
     assert.deepEqual(msg_ids, fixture.expected_msg_ids);
 }
 
diff --git a/frontend_tests/node_tests/narrow_state.js b/frontend_tests/node_tests/narrow_state.js
index 7a5a80770d..b34b6c4d46 100644
--- a/frontend_tests/node_tests/narrow_state.js
+++ b/frontend_tests/node_tests/narrow_state.js
@@ -7,7 +7,7 @@ zrequire('narrow_state');
 set_global('page_params', {});
 
 function set_filter(operators) {
-    operators = operators.map(op => ({
+    operators = operators.map((op) => ({
         operator: op[0],
         operand: op[1],
     }));
diff --git a/frontend_tests/node_tests/people.js b/frontend_tests/node_tests/people.js
index e3e5a10c22..10f5455104 100644
--- a/frontend_tests/node_tests/people.js
+++ b/frontend_tests/node_tests/people.js
@@ -897,7 +897,7 @@ run_test('updates', () => {
     const all_people = get_all_persons();
     assert.equal(all_people.length, 2);
 
-    person = all_people.filter(p => p.email === new_email)[0];
+    person = all_people.filter((p) => p.email === new_email)[0];
     assert.equal(person.full_name, 'Foo Barson');
 
     // Test shim where we can still retrieve user info using the
diff --git a/frontend_tests/node_tests/pm_list.js b/frontend_tests/node_tests/pm_list.js
index 98461246fd..418fd21f54 100644
--- a/frontend_tests/node_tests/pm_list.js
+++ b/frontend_tests/node_tests/pm_list.js
@@ -2,7 +2,7 @@ set_global('$', global.make_zjquery());
 
 set_global('narrow_state', {});
 set_global('ui', {
-    get_content_element: element => element,
+    get_content_element: (element) => element,
 });
 set_global('stream_popover', {
     hide_topic_popover: function () {},
diff --git a/frontend_tests/node_tests/reactions.js b/frontend_tests/node_tests/reactions.js
index 45befca599..365b9826f7 100644
--- a/frontend_tests/node_tests/reactions.js
+++ b/frontend_tests/node_tests/reactions.js
@@ -420,7 +420,7 @@ run_test('add_and_remove_reaction', () => {
 
     const result = reactions.get_message_reactions(message);
     assert(reaction_element.hasClass('reacted'));
-    const realm_emoji_data = result.filter(v => v.emoji_name === 'realm_emoji')[0];
+    const realm_emoji_data = result.filter((v) => v.emoji_name === 'realm_emoji')[0];
 
     assert.equal(realm_emoji_data.count, 2);
     assert.equal(realm_emoji_data.is_realm_emoji, true);
diff --git a/frontend_tests/node_tests/recent_senders.js b/frontend_tests/node_tests/recent_senders.js
index 6cdf6fb7f9..54aa83666d 100644
--- a/frontend_tests/node_tests/recent_senders.js
+++ b/frontend_tests/node_tests/recent_senders.js
@@ -5,7 +5,7 @@ const messages = [];
 
 set_global('message_util', {
     get_messages_in_topic: (stream_id, topic) => {
-        return messages.filter(x => {
+        return messages.filter((x) => {
             return x.stream_id === stream_id &&
                    x.topic.toLowerCase() === topic.toLowerCase();
         });
diff --git a/frontend_tests/node_tests/rendered_markdown.js b/frontend_tests/node_tests/rendered_markdown.js
index 9d02349d75..1352450a14 100644
--- a/frontend_tests/node_tests/rendered_markdown.js
+++ b/frontend_tests/node_tests/rendered_markdown.js
@@ -52,7 +52,7 @@ stream_data.add_sub(stream);
 
 const $array = (array) => {
     const each = (func) => {
-        array.forEach(e => {
+        array.forEach((e) => {
             func.call(e);
         });
     };
diff --git a/frontend_tests/node_tests/scroll_util.js b/frontend_tests/node_tests/scroll_util.js
index b04f182e60..19d3f40bc1 100644
--- a/frontend_tests/node_tests/scroll_util.js
+++ b/frontend_tests/node_tests/scroll_util.js
@@ -1,6 +1,6 @@
 zrequire('scroll_util');
 set_global('ui', {
-    get_scroll_element: element => element,
+    get_scroll_element: (element) => element,
 });
 
 run_test('scroll_delta', () => {
diff --git a/frontend_tests/node_tests/search.js b/frontend_tests/node_tests/search.js
index 4e7a7efc98..8b4a7550df 100644
--- a/frontend_tests/node_tests/search.js
+++ b/frontend_tests/node_tests/search.js
@@ -27,7 +27,7 @@ set_global('search_pill_widget', {
 search_pill.append_search_string = noop;
 search_pill.get_search_string_for_current_filter = noop;
 
-global.patch_builtin('setTimeout', func => func());
+global.patch_builtin('setTimeout', (func) => func());
 
 run_test('clear_search_form', () => {
     $('#search_query').val('noise');
diff --git a/frontend_tests/node_tests/search_legacy.js b/frontend_tests/node_tests/search_legacy.js
index 5ebd1169c6..2d1841ca54 100644
--- a/frontend_tests/node_tests/search_legacy.js
+++ b/frontend_tests/node_tests/search_legacy.js
@@ -17,7 +17,7 @@ set_global('ui_util', {
 set_global('narrow', {});
 set_global('Filter', {});
 
-global.patch_builtin('setTimeout', func => func());
+global.patch_builtin('setTimeout', (func) => func());
 
 run_test('update_button_visibility', () => {
     const search_query = $('#search_query');
diff --git a/frontend_tests/node_tests/settings_org.js b/frontend_tests/node_tests/settings_org.js
index c106611867..fa53843f5f 100644
--- a/frontend_tests/node_tests/settings_org.js
+++ b/frontend_tests/node_tests/settings_org.js
@@ -200,7 +200,7 @@ function test_submit_settings_form(submit_form) {
         realm_create_stream_policy: settings_config.create_stream_policy_values.by_members.code,
     });
 
-    global.patch_builtin('setTimeout', func => func());
+    global.patch_builtin('setTimeout', (func) => func());
     const ev = {
         preventDefault: noop,
         stopPropagation: noop,
@@ -1016,7 +1016,7 @@ run_test('misc', () => {
                              'realm_default_code_block_language'];
     const dropdown_list_parent = $.create(`<list parent>`);
     dropdown_list_parent.set_find_results('.dropdown_list_reset_button:not([disabled])', $.create('<disable button>'));
-    widget_settings.forEach(name => {
+    widget_settings.forEach((name) => {
         const elem = $.create(`#${name}_widget #${name}_name`);
         elem.closest = () => {
             return dropdown_list_parent;
diff --git a/frontend_tests/node_tests/settings_user_groups.js b/frontend_tests/node_tests/settings_user_groups.js
index 7e79f012a2..ff9b977c7c 100644
--- a/frontend_tests/node_tests/settings_user_groups.js
+++ b/frontend_tests/node_tests/settings_user_groups.js
@@ -210,7 +210,7 @@ run_test('populate_user_groups', () => {
 
         (function test_source() {
             const result = config.source.call(fake_context, iago);
-            const emails = result.map(user => user.email).sort();
+            const emails = result.map((user) => user.email).sort();
             assert.deepEqual(emails, [alice.email, bob.email]);
         }());
 
diff --git a/frontend_tests/node_tests/stream_data.js b/frontend_tests/node_tests/stream_data.js
index 5cf005b622..f5cd80e34c 100644
--- a/frontend_tests/node_tests/stream_data.js
+++ b/frontend_tests/node_tests/stream_data.js
@@ -35,7 +35,7 @@ people.add_active_user(me);
 people.initialize_current_user(me.user_id);
 
 function contains_sub(subs, sub) {
-    return subs.some(s => s.name === sub.name);
+    return subs.some((s) => s.name === sub.name);
 }
 
 run_test('basics', () => {
@@ -921,7 +921,7 @@ run_test('initialize', () => {
     initialize();
     assert(!stream_data.is_filtering_inactives());
 
-    const stream_names = stream_data.get_streams_for_admin().map(elem => elem.name);
+    const stream_names = stream_data.get_streams_for_admin().map((elem) => elem.name);
     assert(stream_names.includes('subscriptions'));
     assert(stream_names.includes('unsubscribed'));
     assert(stream_names.includes('never_subscribed'));
diff --git a/frontend_tests/node_tests/stream_list.js b/frontend_tests/node_tests/stream_list.js
index 74705c5a23..a2ed2c6273 100644
--- a/frontend_tests/node_tests/stream_list.js
+++ b/frontend_tests/node_tests/stream_list.js
@@ -390,7 +390,7 @@ run_test('narrowing', () => {
     scroll_util.scroll_element_into_container = noop;
 
     set_global('ui', {
-        get_scroll_element: element => element,
+        get_scroll_element: (element) => element,
     });
 
     assert(!$('<devel sidebar row html>').hasClass('active-filter'));
diff --git a/frontend_tests/node_tests/subs.js b/frontend_tests/node_tests/subs.js
index 0a8a1f417f..defcb98d73 100644
--- a/frontend_tests/node_tests/subs.js
+++ b/frontend_tests/node_tests/subs.js
@@ -1,8 +1,8 @@
 global.stub_out_jquery();
 
 set_global('ui', {
-    get_content_element: element => element,
-    get_scroll_element: element => element,
+    get_content_element: (element) => element,
+    get_scroll_element: (element) => element,
 });
 zrequire('stream_data');
 zrequire('search_util');
diff --git a/frontend_tests/node_tests/topic_list_data.js b/frontend_tests/node_tests/topic_list_data.js
index ad82ec1547..20de9861ee 100644
--- a/frontend_tests/node_tests/topic_list_data.js
+++ b/frontend_tests/node_tests/topic_list_data.js
@@ -81,7 +81,7 @@ run_test('get_list_info unreads', () => {
     // Going forward, we just stub get_recent_topic_names
     // for simpler test setup.
     stream_topic_history.get_recent_topic_names = () => {
-        return _.range(15).map(i => 'topic ' + i);
+        return _.range(15).map((i) => 'topic ' + i);
     };
 
     const unread_cnt = new Map();
@@ -108,7 +108,7 @@ run_test('get_list_info unreads', () => {
     assert.equal(list_info.num_possible_topics, 15);
 
     assert.deepEqual(
-        list_info.items.map(li => li.topic_name),
+        list_info.items.map((li) => li.topic_name),
         [
             'topic 0',
             'topic 1',
@@ -128,7 +128,7 @@ run_test('get_list_info unreads', () => {
     assert.equal(list_info.num_possible_topics, 15);
 
     assert.deepEqual(
-        list_info.items.map(li => li.topic_name),
+        list_info.items.map((li) => li.topic_name),
         [
             'topic 0',
             'topic 1',
@@ -155,7 +155,7 @@ run_test('get_list_info unreads', () => {
     assert.equal(list_info.num_possible_topics, 15);
 
     assert.deepEqual(
-        list_info.items.map(li => li.topic_name),
+        list_info.items.map((li) => li.topic_name),
         [
             'topic 0',
             'topic 1',
diff --git a/frontend_tests/node_tests/typeahead_helper.js b/frontend_tests/node_tests/typeahead_helper.js
index 0477b7c3c4..079017f768 100644
--- a/frontend_tests/node_tests/typeahead_helper.js
+++ b/frontend_tests/node_tests/typeahead_helper.js
@@ -26,8 +26,8 @@ let next_id = 0;
 
 function assertSameEmails(lst1, lst2) {
     assert.deepEqual(
-        lst1.map(r => r.email),
-        lst2.map(r => r.email)
+        lst1.map((r) => r.email),
+        lst2.map((r) => r.email)
     );
 }
 
@@ -211,7 +211,7 @@ function get_typeahead_result(query, current_stream, current_topic) {
         current_stream,
         current_topic
     );
-    return result.map(person => person.email);
+    return result.map((person) => person.email);
 }
 
 run_test('sort_recipients', () => {
@@ -363,7 +363,7 @@ run_test('sort_recipients dup bots', () => {
     const dup_objects = matches.concat([a_bot]);
 
     const recipients = th.sort_recipients(dup_objects, "b", "", "");
-    const recipients_email = recipients.map(person => person.email);
+    const recipients_email = recipients.map((person) => person.email);
     const expected = [
         'b_bot@example.com',
         'b_user_3@zulip.net',
@@ -400,7 +400,7 @@ run_test('sort_recipients subscribers', () => {
     // b_user_2 is a subscriber and b_user_1 is not.
     const small_matches = [b_user_2, b_user_1];
     const recipients = th.sort_recipients(small_matches, "b", "Dev", "Dev Topic");
-    const recipients_email = recipients.map(person => person.email);
+    const recipients_email = recipients.map((person) => person.email);
     const expected = [
         'b_user_2@zulip.net',
         'b_user_1@zulip.net',
@@ -413,7 +413,7 @@ run_test('sort_recipients pm partners', () => {
     // both are not subscribered to the stream Linux.
     const small_matches = [b_user_3, b_user_2];
     const recipients = th.sort_recipients(small_matches, "b", "Linux", "Linux Topic");
-    const recipients_email = recipients.map(person => person.email);
+    const recipients_email = recipients.map((person) => person.email);
     const expected = [
         'b_user_3@zulip.net',
         'b_user_2@zulip.net',
@@ -432,7 +432,7 @@ run_test('sort broadcast mentions', () => {
         '');
 
     assert.deepEqual(
-        results.map(r => r.email),
+        results.map((r) => r.email),
         ['all', 'everyone', 'stream']
     );
 
@@ -449,7 +449,7 @@ run_test('sort broadcast mentions', () => {
         '');
 
     assert.deepEqual(
-        results2.map(r => r.email),
+        results2.map((r) => r.email),
         ['all',
          'everyone',
          'stream',
@@ -709,7 +709,7 @@ run_test('sort_slash_commands', () => {
 
 run_test('sort_recipientbox_typeahead', () => {
     let recipients = th.sort_recipientbox_typeahead("b, a", matches, ""); // search "a"
-    let recipients_email = recipients.map(person => person.email);
+    let recipients_email = recipients.map((person) => person.email);
     assert.deepEqual(recipients_email, [
         'a_user@zulip.org', // matches "a"
         'a_bot@zulip.com', // matches "a"
@@ -721,7 +721,7 @@ run_test('sort_recipientbox_typeahead', () => {
     ]);
 
     recipients = th.sort_recipientbox_typeahead("b, a, b", matches, ""); // search "b"
-    recipients_email = recipients.map(person => person.email);
+    recipients_email = recipients.map((person) => person.email);
     assert.deepEqual(recipients_email, [
         'b_bot@example.com',
         'b_user_3@zulip.net',
diff --git a/frontend_tests/node_tests/ui_init.js b/frontend_tests/node_tests/ui_init.js
index 9d7c925bfc..5f714fb715 100644
--- a/frontend_tests/node_tests/ui_init.js
+++ b/frontend_tests/node_tests/ui_init.js
@@ -72,7 +72,7 @@ emoji.emojis_by_name = new Map();
 
 util.is_mobile = () => false;
 global.stub_templates(() => 'some-html');
-ui.get_scroll_element = element => element;
+ui.get_scroll_element = (element) => element;
 
 zrequire('alert_words');
 zrequire('hash_util');
diff --git a/frontend_tests/node_tests/vdom.js b/frontend_tests/node_tests/vdom.js
index 0549221143..4f85133dfb 100644
--- a/frontend_tests/node_tests/vdom.js
+++ b/frontend_tests/node_tests/vdom.js
@@ -119,7 +119,7 @@ function make_child(i, name) {
 }
 
 function make_children(lst) {
-    return lst.map(i => make_child(i, 'foo' + i));
+    return lst.map((i) => make_child(i, 'foo' + i));
 }
 
 run_test('children', () => {
diff --git a/frontend_tests/puppeteer_lib/common.js b/frontend_tests/puppeteer_lib/common.js
index e9cb62ffe0..782f557d76 100644
--- a/frontend_tests/puppeteer_lib/common.js
+++ b/frontend_tests/puppeteer_lib/common.js
@@ -105,7 +105,7 @@ class CommonUtils {
         // is parsed but before DOMContentLoaded event is fired.
         await Promise.all([
             page.waitForNavigation({ waitUntil: 'domcontentloaded' }),
-            page.$eval('#login_form', form => form.submit()),
+            page.$eval('#login_form', (form) => form.submit()),
         ]);
     }
 
@@ -224,7 +224,7 @@ class CommonUtils {
 
         // confirm if compose box is empty.
         const compose_box_element = await page.$("#compose-textarea");
-        const compose_box_content = await page.evaluate(element => element.textContent,
+        const compose_box_content = await page.evaluate((element) => element.textContent,
                                                         compose_box_element);
         assert.equal(compose_box_content, '', 'Compose box not empty after message sent');
 
diff --git a/frontend_tests/puppeteer_tests/00-realm-creation.js b/frontend_tests/puppeteer_tests/00-realm-creation.js
index 880149e0f1..040dfade58 100644
--- a/frontend_tests/puppeteer_tests/00-realm-creation.js
+++ b/frontend_tests/puppeteer_tests/00-realm-creation.js
@@ -14,7 +14,7 @@ async function realm_creation_tests(page) {
     await page.type('#email', email);
     await Promise.all([
         page.waitForNavigation(),
-        page.$eval('#send_confirm', form => form.submit()),
+        page.$eval('#send_confirm', (form) => form.submit()),
     ]);
 
     // Make sure onfirmation email is sent.
@@ -53,9 +53,9 @@ async function realm_creation_tests(page) {
     };
     // For some reason, page.click() does not work this for particular checkbox
     // so use page.$eval here to call the .click method in the browser.
-    await page.$eval('#realm_in_root_domain', el => el.click());
+    await page.$eval('#realm_in_root_domain', (el) => el.click());
     await common.fill_form(page, '#registration', params);
-    await page.$eval('#registration', form => form.submit());
+    await page.$eval('#registration', (form) => form.submit());
 
     // Check if realm is created and user is logged in by checking if
     // element of id `lightbox_overlay` exists.
diff --git a/frontend_tests/zjsunit/handlebars.js b/frontend_tests/zjsunit/handlebars.js
index 209babfaf7..1b0167d8f8 100644
--- a/frontend_tests/zjsunit/handlebars.js
+++ b/frontend_tests/zjsunit/handlebars.js
@@ -7,7 +7,7 @@ const templates_path = path.resolve(__dirname, "../../static/templates");
 
 exports.make_handlebars = () => Handlebars.create();
 
-exports.stub_templates = stub => {
+exports.stub_templates = (stub) => {
     window.template_stub = stub;
 };
 
diff --git a/frontend_tests/zjsunit/i18n.js b/frontend_tests/zjsunit/i18n.js
index ba3d7f3bed..888ef46718 100644
--- a/frontend_tests/zjsunit/i18n.js
+++ b/frontend_tests/zjsunit/i18n.js
@@ -17,7 +17,7 @@ exports.t = function (str, context) {
     */
     const keyword_regex = /__(- )?(\w)+__/g;
     const keys_in_str = str.match(keyword_regex) || [];
-    const substitutions = keys_in_str.map(key => {
+    const substitutions = keys_in_str.map((key) => {
         let prefix_length;
         if (key.startsWith("__- ")) {
             prefix_length = 4;
diff --git a/frontend_tests/zjsunit/index.js b/frontend_tests/zjsunit/index.js
index 62b286f564..18547b5016 100644
--- a/frontend_tests/zjsunit/index.js
+++ b/frontend_tests/zjsunit/index.js
@@ -79,7 +79,7 @@ global.read_fixture_data = (fn) => {
 function short_tb(tb) {
     const lines = tb.split('\n');
 
-    const i = lines.findIndex(line => line.includes('run_test') || line.includes('run_one_module'));
+    const i = lines.findIndex((line) => line.includes('run_test') || line.includes('run_one_module'));
 
     if (i === -1) {
         return tb;
diff --git a/frontend_tests/zjsunit/zblueslip.js b/frontend_tests/zjsunit/zblueslip.js
index 539de29f02..d661a1442f 100644
--- a/frontend_tests/zjsunit/zblueslip.js
+++ b/frontend_tests/zjsunit/zblueslip.js
@@ -41,7 +41,7 @@ exports.make_zblueslip = function () {
         for (const name of names) {
             for (const obj of lib.test_logs[name]) {
                 const message = obj.message;
-                const i = lib.test_data[name].findIndex(x => x.message === message);
+                const i = lib.test_data[name].findIndex((x) => x.message === message);
                 if (i === -1) {
                     // Only throw this for message types we want to explicitly track.
                     // For example, we do not want to throw here for debug messages.
@@ -99,7 +99,7 @@ exports.make_zblueslip = function () {
                 }
             }
             lib.test_logs[name].push({message, more_info, stack});
-            const matched_error_message = lib.test_data[name].find(x => x.message === message);
+            const matched_error_message = lib.test_data[name].find((x) => x.message === message);
             const exact_match_fail = !matched_error_message;
             if (exact_match_fail) {
                 const error = Error(`Invalid ${name} message: "${message}".`);
diff --git a/frontend_tests/zjsunit/zjquery.js b/frontend_tests/zjsunit/zjquery.js
index e48f2cabca..bb6beeb56d 100644
--- a/frontend_tests/zjsunit/zjquery.js
+++ b/frontend_tests/zjsunit/zjquery.js
@@ -523,9 +523,9 @@ exports.make_zjquery = function (opts) {
 
     zjquery.state = function () {
         // useful for debugging
-        let res = Array.from(elems.values(), v => v.debug());
+        let res = Array.from(elems.values(), (v) => v.debug());
 
-        res = res.map(v => [v.selector, v.value, v.shown]);
+        res = res.map((v) => [v.selector, v.value, v.shown]);
 
         res.sort();
 
diff --git a/static/js/blueslip.js b/static/js/blueslip.js
index 4aeccf616e..0e60a35e8f 100644
--- a/static/js/blueslip.js
+++ b/static/js/blueslip.js
@@ -37,7 +37,7 @@ Logger.prototype = (function () {
                 pad(now.getUTCSeconds(), 2) + '.' +
                 pad(now.getUTCMilliseconds(), 3) + ' UTC';
 
-            const str_args = args.map(x => typeof x === "object" ? JSON.stringify(x) : x);
+            const str_args = args.map((x) => typeof x === "object" ? JSON.stringify(x) : x);
 
             const log_entry = date_str + " " + name.toUpperCase() +
                 ': ' + str_args.join("");
diff --git a/static/js/bot_data.js b/static/js/bot_data.js
index 33212cbde4..215f24032b 100644
--- a/static/js/bot_data.js
+++ b/static/js/bot_data.js
@@ -30,7 +30,7 @@ exports.all_user_ids = function () {
 exports.add = function (bot) {
     const clean_bot = _.pick(bot, bot_fields);
     bots.set(bot.user_id, clean_bot);
-    const clean_services = bot.services.map(service => _.pick(service, services_fields));
+    const clean_services = bot.services.map((service) => _.pick(service, services_fields));
     services.set(bot.user_id, clean_services);
 
     send_change_event();
diff --git a/static/js/buddy_data.js b/static/js/buddy_data.js
index 55a7780a22..2f44980d60 100644
--- a/static/js/buddy_data.js
+++ b/static/js/buddy_data.js
@@ -116,12 +116,12 @@ function filter_user_ids(user_filter_text, user_ids) {
         return user_ids;
     }
 
-    user_ids = user_ids.filter(user_id => !people.is_my_user_id(user_id));
+    user_ids = user_ids.filter((user_id) => !people.is_my_user_id(user_id));
 
     let search_terms = user_filter_text.toLowerCase().split(/[|,]+/);
-    search_terms = search_terms.map(s => s.trim());
+    search_terms = search_terms.map((s) => s.trim());
 
-    const persons = user_ids.map(user_id => people.get_by_user_id(user_id));
+    const persons = user_ids.map((user_id) => people.get_by_user_id(user_id));
 
     const user_id_dict = people.filter_people_by_search_terms(persons, search_terms);
     return Array.from(user_id_dict.keys());
@@ -306,7 +306,7 @@ function get_user_id_list(user_filter_text) {
         user_ids = presence.get_user_ids();
     }
 
-    user_ids = user_ids.filter(user_id => {
+    user_ids = user_ids.filter((user_id) => {
         const person = people.get_by_user_id(user_id);
 
         if (!person) {
@@ -334,7 +334,7 @@ exports.get_items_for_users = function (user_ids) {
 };
 
 exports.huddle_fraction_present = function (huddle) {
-    const user_ids = huddle.split(',').map(s => parseInt(s, 10));
+    const user_ids = huddle.split(',').map((s) => parseInt(s, 10));
 
     let num_present = 0;
 
diff --git a/static/js/color_data.js b/static/js/color_data.js
index 979a5b0581..55990f29b5 100644
--- a/static/js/color_data.js
+++ b/static/js/color_data.js
@@ -33,7 +33,7 @@ exports.claim_color = function (color) {
 };
 
 exports.claim_colors = function (subs) {
-    const colors = new Set(subs.map(sub => sub.color));
+    const colors = new Set(subs.map((sub) => sub.color));
     colors.forEach(exports.claim_color);
 };
 
diff --git a/static/js/components.js b/static/js/components.js
index cc7e6858b2..3129ed868b 100644
--- a/static/js/components.js
+++ b/static/js/components.js
@@ -103,7 +103,7 @@ exports.toggle = function (opts) {
         maybe_go_right: maybe_go_right,
 
         disable_tab: function (name) {
-            const value = opts.values.find(o => o.key === name);
+            const value = opts.values.find((o) => o.key === name);
 
             const idx = opts.values.indexOf(value);
             meta.$ind_tab.eq(idx).addClass('disabled');
@@ -121,7 +121,7 @@ exports.toggle = function (opts) {
         // go through the process of finding the correct tab for a given name,
         // and when found, select that one and provide the proper callback.
         goto: function (name) {
-            const value = opts.values.find(o => o.label === name || o.key === name);
+            const value = opts.values.find((o) => o.label === name || o.key === name);
 
             const idx = opts.values.indexOf(value);
 
diff --git a/static/js/compose.js b/static/js/compose.js
index 7d9294ec1b..8cdb82a413 100644
--- a/static/js/compose.js
+++ b/static/js/compose.js
@@ -423,7 +423,7 @@ exports.get_invalid_recipient_emails = function () {
     const private_recipients = util.extract_pm_recipients(
         compose_state.private_message_recipient());
     const invalid_recipients = private_recipients.filter(
-        email => !people.is_valid_email_for_compose(email)
+        (email) => !people.is_valid_email_for_compose(email)
     );
 
     return invalid_recipients;
@@ -916,7 +916,7 @@ exports.warn_if_mentioning_unsubscribed_user = function (mentioned) {
         const error_area = $("#compose_invite_users");
         const existing_invites_area = $('#compose_invite_users .compose_invite_user');
 
-        const existing_invites = Array.from($(existing_invites_area), user_row => {
+        const existing_invites = Array.from($(existing_invites_area), (user_row) => {
             return parseInt($(user_row).data('user-id'), 10);
         });
 
diff --git a/static/js/compose_ui.js b/static/js/compose_ui.js
index 7b3d20531c..89efdc4135 100644
--- a/static/js/compose_ui.js
+++ b/static/js/compose_ui.js
@@ -92,7 +92,7 @@ exports.compute_placeholder_text = function (opts) {
     // For Private Messages
     if (opts.private_message_recipient) {
         const recipient_list = opts.private_message_recipient.split(",");
-        const recipient_names = recipient_list.map(recipient => {
+        const recipient_names = recipient_list.map((recipient) => {
             const user = people.get_by_email(recipient);
             return user.full_name;
         }).join(", ");
diff --git a/static/js/composebox_typeahead.js b/static/js/composebox_typeahead.js
index 06b3cb24f7..a99d074e56 100644
--- a/static/js/composebox_typeahead.js
+++ b/static/js/composebox_typeahead.js
@@ -381,7 +381,7 @@ function should_show_custom_query(query, items) {
     if (!query) {
         return false;
     }
-    const matched = items.some(elem => elem.toLowerCase() === query.toLowerCase());
+    const matched = items.some((elem) => elem.toLowerCase() === query.toLowerCase());
     return !matched;
 }
 
@@ -590,7 +590,7 @@ exports.get_sorted_filtered_items = function (query) {
 exports.filter_and_sort_candidates = function (completing, candidates, token) {
     const matcher = exports.compose_content_matcher(completing, token);
 
-    const small_results = candidates.filter(item => matcher(item));
+    const small_results = candidates.filter((item) => matcher(item));
 
     const sorted_results = exports.sort_results(completing, small_results, token);
 
diff --git a/static/js/drafts.js b/static/js/drafts.js
index b73a9aee4e..a58f176393 100644
--- a/static/js/drafts.js
+++ b/static/js/drafts.js
@@ -245,7 +245,7 @@ exports.format_draft = function (draft) {
         };
     } else {
         const emails = util.extract_pm_recipients(draft.private_message_recipient);
-        const recipients = emails.map(email => {
+        const recipients = emails.map((email) => {
             email = email.trim();
             const person = people.get_by_email(email);
             if (person !== undefined) {
diff --git a/static/js/dropdown_list_widget.js b/static/js/dropdown_list_widget.js
index da5360006e..ca6ee5df14 100644
--- a/static/js/dropdown_list_widget.js
+++ b/static/js/dropdown_list_widget.js
@@ -30,7 +30,7 @@ const DropdownListWidget = function (opts) {
         }
 
         // Happy path
-        const item = opts.data.find(x => x.value === value.toString());
+        const item = opts.data.find((x) => x.value === value.toString());
         const text = opts.render_text(item.name);
         elem.text(text);
         elem.removeClass('text-warning');
diff --git a/static/js/echo.js b/static/js/echo.js
index aa48e6f801..6b9ee72c9e 100644
--- a/static/js/echo.js
+++ b/static/js/echo.js
@@ -52,7 +52,7 @@ exports.build_display_recipient = function (message) {
     const emails = util.extract_pm_recipients(message.private_message_recipient);
 
     let sender_in_display_recipients = false;
-    const display_recipient = emails.map(email => {
+    const display_recipient = emails.map((email) => {
         email = email.trim();
         const person = people.get_by_email(email);
         if (person === undefined) {
diff --git a/static/js/emoji_picker.js b/static/js/emoji_picker.js
index e3b3bd51b1..a19f370faf 100644
--- a/static/js/emoji_picker.js
+++ b/static/js/emoji_picker.js
@@ -103,7 +103,7 @@ function show_emoji_catalog() {
 
 exports.generate_emoji_picker_data = function (realm_emojis) {
     const catalog = new Map();
-    catalog.set("Custom", Array.from(realm_emojis.keys(), realm_emoji_name =>
+    catalog.set("Custom", Array.from(realm_emojis.keys(), (realm_emoji_name) =>
         emoji.emojis_by_name.get(realm_emoji_name)
     ));
 
@@ -133,8 +133,8 @@ exports.generate_emoji_picker_data = function (realm_emojis) {
     }
     catalog.set("Popular", popular);
 
-    const categories = get_all_emoji_categories().filter(category => catalog.has(category.name));
-    exports.complete_emoji_catalog = categories.map(category => ({
+    const categories = get_all_emoji_categories().filter((category) => catalog.has(category.name));
+    exports.complete_emoji_catalog = categories.map((category) => ({
         name: category.name,
         icon: category.icon,
         emojis: catalog.get(category.name),
@@ -148,7 +148,7 @@ const generate_emoji_picker_content = function (id) {
         emojis_used = reactions.get_emojis_used_by_user_for_message_id(id);
     }
     for (const emoji_dict of emoji.emojis_by_name.values()) {
-        emoji_dict.has_reacted = emoji_dict.aliases.some(alias => emojis_used.includes(alias));
+        emoji_dict.has_reacted = emoji_dict.aliases.some((alias) => emojis_used.includes(alias));
     }
 
     return render_emoji_popover_content({
@@ -212,7 +212,7 @@ function filter_emojis() {
 
             for (const emoji_dict of emojis) {
                 for (const alias of emoji_dict.aliases) {
-                    const match = search_terms.every(search_term => alias.includes(search_term));
+                    const match = search_terms.every((search_term) => alias.includes(search_term));
                     if (match) {
                         search_results.push({ ...emoji_dict, name: alias });
                         break;  // We only need the first matching alias per emoji.
diff --git a/static/js/fenced_code.js b/static/js/fenced_code.js
index e70b214f8b..5ccec58942 100644
--- a/static/js/fenced_code.js
+++ b/static/js/fenced_code.js
@@ -42,7 +42,7 @@ function wrap_quote(text) {
     // beginning of each line
     for (const paragraph of paragraphs) {
         const lines = paragraph.split('\n');
-        quoted_paragraphs.push(lines.filter(line => line !== '').map(line => '> ' + line).join('\n'));
+        quoted_paragraphs.push(lines.filter((line) => line !== '').map((line) => '> ' + line).join('\n'));
     }
 
     return quoted_paragraphs.join('\n\n');
diff --git a/static/js/filter.js b/static/js/filter.js
index 436a742f27..95c2b4bd89 100644
--- a/static/js/filter.js
+++ b/static/js/filter.js
@@ -323,7 +323,7 @@ Filter.parse = function (str) {
    might need to support multiple operators of the same type.
 */
 Filter.unparse = function (operators) {
-    const parts = operators.map(elem => {
+    const parts = operators.map((elem) => {
 
         if (elem.operator === 'search') {
             // Search terms are the catch-all case.
@@ -357,7 +357,7 @@ Filter.prototype = {
     public_operators: function () {
         const safe_to_return = this._operators.filter(
             // Filter out the embedded narrow (if any).
-            value =>
+            (value) =>
                 !(
                     page_params.narrow_stream !== undefined &&
                     value.operator === "stream" &&
@@ -376,18 +376,18 @@ Filter.prototype = {
 
     has_negated_operand: function (operator, operand) {
         return this._operators.some(
-            elem => elem.negated && (elem.operator === operator && elem.operand === operand)
+            (elem) => elem.negated && (elem.operator === operator && elem.operand === operand)
         );
     },
 
     has_operand: function (operator, operand) {
         return this._operators.some(
-            elem => !elem.negated && (elem.operator === operator && elem.operand === operand)
+            (elem) => !elem.negated && (elem.operator === operator && elem.operand === operand)
         );
     },
 
     has_operator: function (operator) {
-        return this._operators.some(elem => {
+        return this._operators.some((elem) => {
             if (elem.negated && !['search', 'has'].includes(elem.operator)) {
                 return false;
             }
@@ -591,7 +591,7 @@ Filter.prototype = {
                 return i18n.t('Private messages');
             case 'pm-with': {
                 const emails = this.operands('pm-with')[0].split(',');
-                const names = emails.map(email => {
+                const names = emails.map((email) => {
                     if (!people.get_by_email(email)) {
                         return email;
                     }
@@ -673,15 +673,15 @@ Filter.prototype = {
             return terms;
         }
 
-        return terms.filter(term => Filter.term_type(term) !== 'is-private');
+        return terms.filter((term) => Filter.term_type(term) !== 'is-private');
     },
 
     _canonicalize_operators: function (operators_mixed_case) {
-        return operators_mixed_case.map(tuple => Filter.canonicalize_term(tuple));
+        return operators_mixed_case.map((tuple) => Filter.canonicalize_term(tuple));
     },
 
     filter_with_new_params: function (params) {
-        const terms = this._operators.map(term => {
+        const terms = this._operators.map((term) => {
             const new_term = { ...term };
             if (new_term.operator === params.operator && !new_term.negated) {
                 new_term.operand = params.operand;
@@ -729,7 +729,7 @@ Filter.prototype = {
     first_valid_id_from: function (msg_ids) {
         const predicate = this.predicate();
 
-        const first_id = msg_ids.find(msg_id => {
+        const first_id = msg_ids.find((msg_id) => {
             const message = message_store.get(msg_id);
 
             if (message === undefined) {
@@ -771,7 +771,7 @@ Filter.prototype = {
         // build JavaScript code in a string and then eval() it.
 
         return function (message) {
-            return operators.every(term => {
+            return operators.every((term) => {
                 let ok = message_matches_search_term(message, term.operator, term.operand);
                 if (term.negated) {
                     ok = !ok;
@@ -910,7 +910,7 @@ function describe_unescaped(operators) {
         }
     }
 
-    const more_parts = operators.map(elem => {
+    const more_parts = operators.map((elem) => {
         const operand = elem.operand;
         const canonicalized_operator = Filter.canonicalize_operator(elem.operator);
         if (canonicalized_operator === 'is') {
diff --git a/static/js/hotspots.js b/static/js/hotspots.js
index 09a4276cd8..8586a1294b 100644
--- a/static/js/hotspots.js
+++ b/static/js/hotspots.js
@@ -237,7 +237,7 @@ exports.close_hotspot_icon = function (elem) {
 function close_read_hotspots(new_hotspots) {
     const unwanted_hotspots = _.difference(
         Array.from(HOTSPOT_LOCATIONS.keys()),
-        new_hotspots.map(hotspot => hotspot.name)
+        new_hotspots.map((hotspot) => hotspot.name)
     );
 
     for (const hotspot_name of unwanted_hotspots) {
diff --git a/static/js/info_overlay.js b/static/js/info_overlay.js
index e486489900..b073c5daca 100644
--- a/static/js/info_overlay.js
+++ b/static/js/info_overlay.js
@@ -22,7 +22,7 @@ exports.set_up_toggler = function () {
     const elem = exports.toggler.get();
     elem.addClass('large allow-overflow');
 
-    const modals = opts.values.map(item => {
+    const modals = opts.values.map((item) => {
         const key = item.key; // e.g. message-formatting
         const modal = $('#' + key).find('.modal-body');
         return modal;
diff --git a/static/js/input_pill.js b/static/js/input_pill.js
index b5cb93246b..1468187733 100644
--- a/static/js/input_pill.js
+++ b/static/js/input_pill.js
@@ -219,11 +219,11 @@ exports.create = function (opts) {
         },
 
         getByID: function (id) {
-            return store.pills.find(pill => pill.id === id);
+            return store.pills.find((pill) => pill.id === id);
         },
 
         items: function () {
-            return store.pills.map(pill => pill.item);
+            return store.pills.map((pill) => pill.item);
         },
 
         createPillonPaste: function () {
diff --git a/static/js/markdown.js b/static/js/markdown.js
index b9348ff660..7b7d9abc5d 100644
--- a/static/js/markdown.js
+++ b/static/js/markdown.js
@@ -71,12 +71,12 @@ exports.contains_backend_only_syntax = function (content) {
     // Try to guess whether or not a message contains syntax that only the
     // backend markdown processor can correctly handle.
     // If it doesn't, we can immediately render it client-side for local echo.
-    const markedup = backend_only_markdown_re.find(re => re.test(content));
+    const markedup = backend_only_markdown_re.find((re) => re.test(content));
 
     // If a realm filter doesn't start with some specified characters
     // then don't render it locally. It is workaround for the fact that
     // javascript regex doesn't support lookbehind.
-    const false_filter_match = realm_filter_list.find(re => {
+    const false_filter_match = realm_filter_list.find((re) => {
         const pattern = /(?:[^\s'"\(,:<])/.source + re[0].source + /(?![\w])/.source;
         const regex = new RegExp(pattern);
         return regex.test(content);
@@ -455,7 +455,7 @@ exports.initialize = function (realm_filters, helper_config) {
 
     // No <code> around our code blocks instead a codehilite <div> and disable
     // class-specific highlighting.
-    r.code = code => fenced_code.wrap_code(code) + '\n\n';
+    r.code = (code) => fenced_code.wrap_code(code) + '\n\n';
 
     // Prohibit empty links for some reason.
     const old_link = r.link;
diff --git a/static/js/message_edit.js b/static/js/message_edit.js
index 73ced39dc1..c98f1c8437 100644
--- a/static/js/message_edit.js
+++ b/static/js/message_edit.js
@@ -271,7 +271,7 @@ function edit_message(row, raw_content) {
     const show_edit_stream = message.is_stream && page_params.is_admin;
     // current message's stream has been already been added and selected in handlebar
     const available_streams = show_edit_stream ? stream_data.subscribed_subs()
-        .filter(s => s.stream_id !== message.stream_id) : null;
+        .filter((s) => s.stream_id !== message.stream_id) : null;
 
     const form = $(render_message_edit_form({
         is_stream: message.type === 'stream',
@@ -817,13 +817,13 @@ exports.delete_message = function (msg_id) {
             success: function () {
                 $('#delete_message_modal').modal("hide");
                 currently_deleting_messages = currently_deleting_messages.filter(
-                    id => id !== msg_id
+                    (id) => id !== msg_id
                 );
                 hide_delete_btn_show_spinner(false);
             },
             error: function (xhr) {
                 currently_deleting_messages = currently_deleting_messages.filter(
-                    id => id !== msg_id
+                    (id) => id !== msg_id
                 );
                 hide_delete_btn_show_spinner(false);
                 ui_report.error(i18n.t("Error deleting message"), xhr,
diff --git a/static/js/message_fetch.js b/static/js/message_fetch.js
index bb426c69e1..344f83d37a 100644
--- a/static/js/message_fetch.js
+++ b/static/js/message_fetch.js
@@ -131,7 +131,7 @@ function handle_operators_supporting_id_based_api(data) {
     }
 
     data.narrow = JSON.parse(data.narrow);
-    data.narrow = data.narrow.map(filter => {
+    data.narrow = data.narrow.map((filter) => {
         if (operators_supporting_ids.includes(filter.operator)) {
             filter.operand = people.emails_strings_to_user_ids_array(filter.operand);
         }
diff --git a/static/js/message_flags.js b/static/js/message_flags.js
index 4df205fc85..d1fb7bebf1 100644
--- a/static/js/message_flags.js
+++ b/static/js/message_flags.js
@@ -16,8 +16,8 @@ exports.send_read = (function () {
     let start;
     function server_request() {
         // Wait for server IDs before sending flags
-        const real_msgs = queue.filter(msg => !msg.locally_echoed);
-        const real_msg_ids = real_msgs.map(msg => msg.id);
+        const real_msgs = queue.filter((msg) => !msg.locally_echoed);
+        const real_msg_ids = real_msgs.map((msg) => msg.id);
 
         if (real_msg_ids.length === 0) {
             setTimeout(start, 100);
@@ -46,7 +46,7 @@ exports.send_read = (function () {
             return;
         }
 
-        queue = queue.filter(message => !data.messages.includes(message.id));
+        queue = queue.filter((message) => !data.messages.includes(message.id));
 
         if (queue.length > 0) {
             start();
diff --git a/static/js/message_list_data.js b/static/js/message_list_data.js
index 9338ba81c5..6db6af76d5 100644
--- a/static/js/message_list_data.js
+++ b/static/js/message_list_data.js
@@ -43,7 +43,7 @@ MessageListData.prototype = {
         if (this._selected_id === -1) {
             return;
         }
-        const ids = this._items.map(message => message.id);
+        const ids = this._items.map((message) => message.id);
 
         const i = ids.indexOf(this._selected_id);
         if (i === -1) {
@@ -158,7 +158,7 @@ MessageListData.prototype = {
     valid_non_duplicated_messages: function (messages) {
         const predicate = this._get_predicate();
         const self = this;
-        return messages.filter(msg => self.get(msg.id) === undefined && predicate(msg));
+        return messages.filter((msg) => self.get(msg.id) === undefined && predicate(msg));
     },
 
     filter_incoming: function (messages) {
@@ -168,7 +168,7 @@ MessageListData.prototype = {
 
     unmuted_messages: function (messages) {
         return messages.filter(
-            message =>
+            (message) =>
                 !muting.is_topic_muted(message.stream_id, message.topic) ||
                 message.mentioned
         );
@@ -182,7 +182,7 @@ MessageListData.prototype = {
     },
 
     first_unread_message_id: function () {
-        const first_unread = this._items.find(message => unread.message_unread(message));
+        const first_unread = this._items.find((message) => unread.message_unread(message));
 
         if (first_unread) {
             return first_unread.id;
@@ -231,7 +231,7 @@ MessageListData.prototype = {
         // bottom_messages regardless
         if (self.selected_id() === -1 && self.empty()) {
             const narrow_messages = self.filter_incoming(messages);
-            bottom_messages = narrow_messages.filter(msg => !self.get(msg.id));
+            bottom_messages = narrow_messages.filter((msg) => !self.get(msg.id));
         } else {
             // Filter out duplicates that are already in self, and all messages
             // that fail our filter predicate
@@ -342,10 +342,10 @@ MessageListData.prototype = {
             msg_ids_to_remove.add(message.id);
         }
 
-        this._items = this._items.filter(message => !msg_ids_to_remove.has(message.id));
+        this._items = this._items.filter((message) => !msg_ids_to_remove.has(message.id));
         if (this.muting_enabled) {
             this._all_items = this._all_items.filter(
-                message => !msg_ids_to_remove.has(message.id)
+                (message) => !msg_ids_to_remove.has(message.id)
             );
         }
     },
diff --git a/static/js/message_list_view.js b/static/js/message_list_view.js
index 579436a335..bd5d0e7414 100644
--- a/static/js/message_list_view.js
+++ b/static/js/message_list_view.js
@@ -562,7 +562,7 @@ MessageListView.prototype = {
         // all messages lists. To prevent having both list views overwriting
         // each others data we will make a new message object to add data to
         // for rendering.
-        const message_containers = messages.map(message => {
+        const message_containers = messages.map((message) => {
             if (message.starred) {
                 message.starred_status = i18n.t("Unstar");
             } else {
@@ -671,7 +671,7 @@ MessageListView.prototype = {
         if (message_actions.append_messages.length > 0) {
             last_message_row = table.find('.message_row').last().expectOne();
             last_group_row = rows.get_message_recipient_row(last_message_row);
-            dom_messages = $(message_actions.append_messages.map(message_container => self._get_message_template(message_container)).join('')).filter('.message_row');
+            dom_messages = $(message_actions.append_messages.map((message_container) => self._get_message_template(message_container)).join('')).filter('.message_row');
 
             self._post_process(dom_messages);
             last_group_row.append(dom_messages);
@@ -1026,7 +1026,7 @@ MessageListView.prototype = {
             // Since we don't have a way to get a message group from
             // the containing message container, we just do a search
             // to find it.
-            message_group => message_group.message_group_id === message_group_id
+            (message_group) => message_group.message_group_id === message_group_id
         );
     },
 
@@ -1097,10 +1097,10 @@ MessageListView.prototype = {
         const self = this;
 
         // Convert messages to list messages
-        let message_containers = messages.map(message => self.message_containers.get(message.id));
+        let message_containers = messages.map((message) => self.message_containers.get(message.id));
         // We may not have the message_container if the stream or topic was muted
         message_containers = message_containers.filter(
-            message_container => message_container !== undefined
+            (message_container) => message_container !== undefined
         );
 
         const message_groups = [];
diff --git a/static/js/message_util.js b/static/js/message_util.js
index dca374b1e3..19120c06a6 100644
--- a/static/js/message_util.js
+++ b/static/js/message_util.js
@@ -49,7 +49,7 @@ exports.get_messages_in_topic = function (stream_id, topic) {
     // all the messages. Please only use it in case of
     // very rare events like topic edits. Its primary
     // use case is the new experimental Recent Topics UI.
-    return message_list.all.all_messages().filter(x => {
+    return message_list.all.all_messages().filter((x) => {
         return x.type === 'stream' &&
                x.stream_id === stream_id &&
                x.topic.toLowerCase() === topic.toLowerCase();
diff --git a/static/js/narrow.js b/static/js/narrow.js
index e1c6d13aa6..e39567ce7f 100644
--- a/static/js/narrow.js
+++ b/static/js/narrow.js
@@ -151,7 +151,7 @@ exports.activate = function (raw_operators, opts) {
     message_scroll.hide_top_of_narrow_notices();
     message_scroll.hide_indicators();
 
-    blueslip.debug("Narrowed", {operators: operators.map(e => e.operator),
+    blueslip.debug("Narrowed", {operators: operators.map((e) => e.operator),
                                 trigger: opts ? opts.trigger : undefined,
                                 previous_id: current_msg_list.selected_id()});
 
@@ -725,7 +725,7 @@ exports.to_compose_target = function () {
     if (compose_state.get_message_type() === 'private') {
         const recipient_string = compose_state.private_message_recipient();
         const emails = util.extract_pm_recipients(recipient_string);
-        const invalid = emails.filter(email => !people.is_valid_email_for_compose(email));
+        const invalid = emails.filter((email) => !people.is_valid_email_for_compose(email));
         // If there are no recipients or any recipient is
         // invalid, narrow to all PMs.
         if (emails.length === 0 || invalid.length > 0) {
diff --git a/static/js/people.js b/static/js/people.js
index 93791f6848..f8574fe551 100644
--- a/static/js/people.js
+++ b/static/js/people.js
@@ -41,7 +41,7 @@ exports.init = function () {
 exports.init();
 
 function split_to_ints(lst) {
-    return lst.split(',').map(s => parseInt(s, 10));
+    return lst.split(',').map((s) => parseInt(s, 10));
 }
 
 
@@ -151,7 +151,7 @@ exports.huddle_string = function (message) {
         return;
     }
 
-    let user_ids = message.display_recipient.map(recip => recip.id);
+    let user_ids = message.display_recipient.map((recip) => recip.id);
 
     function is_huddle_recip(user_id) {
         return user_id &&
@@ -173,7 +173,7 @@ exports.huddle_string = function (message) {
 exports.user_ids_string_to_emails_string = function (user_ids_string) {
     const user_ids = split_to_ints(user_ids_string);
 
-    let emails = user_ids.map(user_id => {
+    let emails = user_ids.map((user_id) => {
         const person = people_by_user_id_dict.get(user_id);
         return person && person.email;
     });
@@ -183,7 +183,7 @@ exports.user_ids_string_to_emails_string = function (user_ids_string) {
         return;
     }
 
-    emails = emails.map(email => email.toLowerCase());
+    emails = emails.map((email) => email.toLowerCase());
 
     emails.sort();
 
@@ -192,7 +192,7 @@ exports.user_ids_string_to_emails_string = function (user_ids_string) {
 
 exports.user_ids_string_to_ids_array = function (user_ids_string) {
     const user_ids = user_ids_string.split(',');
-    const ids = user_ids.map(id => Number(id));
+    const ids = user_ids.map((id) => Number(id));
     return ids;
 };
 
@@ -212,7 +212,7 @@ exports.reply_to_to_user_ids_string = function (emails_string) {
     // invalid data.
     const emails = emails_string.split(',');
 
-    let user_ids = emails.map(email => {
+    let user_ids = emails.map((email) => {
         const person = exports.get_by_email(email);
         return person && person.user_id;
     });
@@ -261,7 +261,7 @@ exports.emails_strings_to_user_ids_string = function (emails_string) {
 };
 
 exports.email_list_to_user_ids_string = function (emails) {
-    let user_ids = emails.map(email => {
+    let user_ids = emails.map((email) => {
         const person = exports.get_by_email(email);
         return person && person.user_id;
     });
@@ -277,7 +277,7 @@ exports.email_list_to_user_ids_string = function (emails) {
 };
 
 exports.safe_full_names = function (user_ids) {
-    let names = user_ids.map(user_id => {
+    let names = user_ids.map((user_id) => {
         const person = people_by_user_id_dict.get(user_id);
         return person && person.full_name;
     });
@@ -295,7 +295,7 @@ exports.get_recipients = function (user_ids_string) {
     // See message_store.get_pm_full_names() for a similar function.
 
     const user_ids = split_to_ints(user_ids_string);
-    const other_ids = user_ids.filter(user_id => !exports.is_my_user_id(user_id));
+    const other_ids = user_ids.filter((user_id) => !exports.is_my_user_id(user_id));
 
     if (other_ids.length === 0) {
         // private message with oneself
@@ -323,7 +323,7 @@ exports.pm_reply_to = function (message) {
         return;
     }
 
-    const emails = user_ids.map(user_id => {
+    const emails = user_ids.map((user_id) => {
         const person = people_by_user_id_dict.get(user_id);
         if (!person) {
             blueslip.error('Unknown user id in message: ' + user_id);
@@ -343,7 +343,7 @@ function sorted_other_user_ids(user_ids) {
     // This excludes your own user id unless you're the only user
     // (i.e. you sent a message to yourself).
 
-    const other_user_ids = user_ids.filter(user_id => !exports.is_my_user_id(user_id));
+    const other_user_ids = user_ids.filter((user_id) => !exports.is_my_user_id(user_id));
 
     if (other_user_ids.length >= 1) {
         user_ids = other_user_ids;
@@ -389,7 +389,7 @@ exports.all_user_ids_in_pm = function (message) {
         return;
     }
 
-    let user_ids = message.display_recipient.map(recip => recip.id);
+    let user_ids = message.display_recipient.map((recip) => recip.id);
 
     user_ids = sort_numerically(user_ids);
     return user_ids;
@@ -405,7 +405,7 @@ exports.pm_with_user_ids = function (message) {
         return;
     }
 
-    const user_ids = message.display_recipient.map(recip => recip.id);
+    const user_ids = message.display_recipient.map((recip) => recip.id);
 
     return sorted_other_user_ids(user_ids);
 };
@@ -420,8 +420,8 @@ exports.group_pm_with_user_ids = function (message) {
         return;
     }
 
-    const user_ids = message.display_recipient.map(recip => recip.id);
-    const is_user_present = user_ids.some(user_id => exports.is_my_user_id(user_id));
+    const user_ids = message.display_recipient.map((recip) => recip.id);
+    const is_user_present = user_ids.some((user_id) => exports.is_my_user_id(user_id));
     if (is_user_present) {
         user_ids.sort();
         if (user_ids.length > 2) {
@@ -483,19 +483,19 @@ exports.update_email_in_reply_to = function (reply_to, user_id, new_email) {
     // and we don't warn on any errors.
     let emails = reply_to.split(',');
 
-    const persons = emails.map(email => people_dict.get(email.trim()));
+    const persons = emails.map((email) => people_dict.get(email.trim()));
 
     if (!persons.every(Boolean)) {
         return reply_to;
     }
 
-    const needs_patch = persons.some(person => person.user_id === user_id);
+    const needs_patch = persons.some((person) => person.user_id === user_id);
 
     if (!needs_patch) {
         return reply_to;
     }
 
-    emails = persons.map(person => {
+    emails = persons.map((person) => {
         if (person.user_id === user_id) {
             return new_email;
         }
@@ -507,8 +507,8 @@ exports.update_email_in_reply_to = function (reply_to, user_id, new_email) {
 
 exports.pm_with_operand_ids = function (operand) {
     let emails = operand.split(',');
-    emails = emails.map(email => email.trim());
-    let persons = emails.map(email => people_dict.get(email));
+    emails = emails.map((email) => email.trim());
+    let persons = emails.map((email) => people_dict.get(email));
 
     // If your email is included in a PM group with other people, just ignore it
     if (persons.length > 1) {
@@ -519,7 +519,7 @@ exports.pm_with_operand_ids = function (operand) {
         return;
     }
 
-    let user_ids = persons.map(person => person.user_id);
+    let user_ids = persons.map((person) => person.user_id);
 
     user_ids = sort_numerically(user_ids);
 
@@ -579,7 +579,7 @@ exports.exclude_me_from_string = function (user_ids_string) {
         return user_ids.join(',');
     }
 
-    user_ids = user_ids.filter(user_id => !exports.is_my_user_id(user_id));
+    user_ids = user_ids.filter((user_id) => !exports.is_my_user_id(user_id));
 
     return user_ids.join(',');
 };
@@ -700,7 +700,7 @@ exports.is_valid_email_for_compose = function (email) {
 
 exports.is_valid_bulk_emails_for_compose = function (emails) {
     // Returns false if at least one of the emails is invalid.
-    return emails.every(email => {
+    return emails.every((email) => {
         if (!exports.is_valid_email_for_compose(email)) {
             return false;
         }
@@ -851,7 +851,7 @@ exports.get_message_people = function () {
         semantics
     */
     const message_people = message_store.user_ids().map(
-        user_id => people_by_user_id_dict.get(user_id)
+        (user_id) => people_by_user_id_dict.get(user_id)
     ).filter(Boolean);
 
     return message_people;
@@ -892,7 +892,7 @@ exports.build_termlet_matcher = function (termlet) {
         }
         const names = full_name.toLowerCase().split(' ');
 
-        return names.some(name => name.startsWith(termlet));
+        return names.some((name) => name.startsWith(termlet));
     };
 };
 
@@ -909,7 +909,7 @@ exports.build_person_matcher = function (query) {
             return true;
         }
 
-        return termlet_matchers.every(matcher => matcher(user));
+        return termlet_matchers.every((matcher) => matcher(user));
     };
 };
 
@@ -918,7 +918,7 @@ exports.filter_people_by_search_terms = function (users, search_terms) {
 
     // Build our matchers outside the loop to avoid some
     // search overhead that is not user-specific.
-    const matchers = search_terms.map(search_term => exports.build_person_matcher(search_term));
+    const matchers = search_terms.map((search_term) => exports.build_person_matcher(search_term));
 
     // Loop through users and populate filtered_users only
     // if they include search_terms
@@ -930,7 +930,7 @@ exports.filter_people_by_search_terms = function (users, search_terms) {
         }
 
         // Return user emails that include search terms
-        const match = matchers.some(matcher => matcher(user));
+        const match = matchers.some((matcher) => matcher(user));
 
         if (match) {
             filtered_users.set(person.user_id, true);
@@ -1198,7 +1198,7 @@ exports.filter_for_user_settings_search = function (persons, query) {
 
               See #13554 for more context.
     */
-    return persons.filter(person => exports.matches_user_settings_search(person, query));
+    return persons.filter((person) => exports.matches_user_settings_search(person, query));
 };
 
 exports.maybe_incr_recipient_count = function (message) {
diff --git a/static/js/pm_conversations.js b/static/js/pm_conversations.js
index 8043d30f54..d29ee97f2c 100644
--- a/static/js/pm_conversations.js
+++ b/static/js/pm_conversations.js
@@ -67,7 +67,7 @@ exports.recent = (function () {
     self.get_strings = function () {
         // returns array of structs with user_ids_string and
         // message_id
-        return recent_private_messages.map(conversation => conversation.user_ids_string);
+        return recent_private_messages.map((conversation) => conversation.user_ids_string);
     };
 
     self.initialize = function (params) {
diff --git a/static/js/poll_widget.js b/static/js/poll_widget.js
index 689d40925b..1f29b9b674 100644
--- a/static/js/poll_widget.js
+++ b/static/js/poll_widget.js
@@ -162,7 +162,7 @@ exports.poll_data_holder = function (is_my_poll, question, options) {
 
     // function to check whether option already exists
     self.is_option_present = function (data, latest_option) {
-        return data.some(el => el.option === latest_option);
+        return data.some((el) => el.option === latest_option);
     };
 
     // function to add all options added along with the /poll command
diff --git a/static/js/popovers.js b/static/js/popovers.js
index 945fc34324..eedb742107 100644
--- a/static/js/popovers.js
+++ b/static/js/popovers.js
@@ -447,7 +447,7 @@ exports.toggle_actions_popover = function (element, id) {
 
         const should_display_edit_history_option =
             message.edit_history &&
-            message.edit_history.some(entry => entry.prev_content !== undefined ||
+            message.edit_history.some((entry) => entry.prev_content !== undefined ||
             util.get_edit_event_prev_topic(entry) !== undefined) &&
             page_params.realm_allow_edit_history;
 
diff --git a/static/js/reactions.js b/static/js/reactions.js
index 3c6b90a5da..312dc142f6 100644
--- a/static/js/reactions.js
+++ b/static/js/reactions.js
@@ -347,7 +347,7 @@ exports.remove_reaction = function (event) {
         return;
     }
 
-    r.user_ids = r.user_ids.filter(id => id !== user_id);
+    r.user_ids = r.user_ids.filter((id) => id !== user_id);
     if (r.user_ids.length > 0) {
         exports.update_user_fields(r);
     } else {
diff --git a/static/js/recent_topics.js b/static/js/recent_topics.js
index 819942ca98..1c275d0632 100644
--- a/static/js/recent_topics.js
+++ b/static/js/recent_topics.js
@@ -224,7 +224,7 @@ exports.topic_in_search_results = function (keyword, stream, topic) {
     keyword = keyword.replace(/[.*+?^${}()|[\]\\]/g, '\\$&');
     const text = (stream + ' ' + topic).toLowerCase().replace(/\s+/g, ' ');
     const search_words = keyword.toLowerCase().replace(/\s+/g, ' ').split(' ');
-    return search_words.every(word => {
+    return search_words.every((word) => {
         if (text.search(word) !== -1) {
             return true;
         }
diff --git a/static/js/reminder.js b/static/js/reminder.js
index f4361e1ae8..a5ba1040ac 100644
--- a/static/js/reminder.js
+++ b/static/js/reminder.js
@@ -46,7 +46,7 @@ exports.schedule_message = function (request) {
     const message = raw_message.slice(1).join('\n');
 
     const deferred_message_type = deferred_message_types.filter(
-        props => command_line.match(props.test) !== null
+        (props) => command_line.match(props.test) !== null
     )[0];
     const command = command_line.match(deferred_message_type.test)[0];
 
diff --git a/static/js/search_pill.js b/static/js/search_pill.js
index 4cbc06e011..69e059e707 100644
--- a/static/js/search_pill.js
+++ b/static/js/search_pill.js
@@ -33,7 +33,7 @@ exports.append_search_string = function (search_string, pill_widget) {
 
 exports.get_search_string_for_current_filter = function (pill_widget) {
     const items = pill_widget.items();
-    const search_strings = items.map(item => item.display_value);
+    const search_strings = items.map((item) => item.display_value);
     return search_strings.join(' ');
 };
 
diff --git a/static/js/search_suggestion.js b/static/js/search_suggestion.js
index 17ef14cde6..c74ac1e6c2 100644
--- a/static/js/search_suggestion.js
+++ b/static/js/search_suggestion.js
@@ -20,7 +20,7 @@ function make_person_highlighter(query) {
 
 function match_criteria(operators, criteria) {
     const filter = new Filter(operators);
-    return criteria.some(cr => {
+    return criteria.some((cr) => {
         if (Object.prototype.hasOwnProperty.call(cr, 'operand')) {
             return filter.has_operand(cr.operator, cr.operand);
         }
@@ -48,7 +48,7 @@ function format_as_suggestion(terms) {
 }
 
 function compare_by_huddle(huddle) {
-    huddle = huddle.slice(0, -1).map(person => {
+    huddle = huddle.slice(0, -1).map((person) => {
         person = people.get_by_email(person);
         return person && person.user_id;
     });
@@ -91,14 +91,14 @@ function get_stream_suggestions(last, operators) {
     const query = last.operand;
     let streams = stream_data.subscribed_streams();
 
-    streams = streams.filter(stream => stream_matches_query(stream, query));
+    streams = streams.filter((stream) => stream_matches_query(stream, query));
 
     streams = typeahead_helper.sorter(query, streams);
 
     const regex = typeahead_helper.build_highlight_regex(query);
     const hilite = typeahead_helper.highlight_with_escaping_and_regex;
 
-    const objs = streams.map(stream => {
+    const objs = streams.map((stream) => {
         const prefix = 'stream';
         const highlighted_stream = hilite(regex, stream);
         const verb = last.negated ? 'exclude ' : '';
@@ -159,7 +159,7 @@ function get_group_suggestions(last, operators) {
 
     const highlight_person = make_person_highlighter(last_part);
 
-    const suggestions = persons.map(person => {
+    const suggestions = persons.map((person) => {
         const term = {
             operator: 'pm-with',
             operand: all_but_last_part + ',' + person.email,
@@ -239,7 +239,7 @@ function get_person_suggestions(people_getter, last, operators, autocomplete_ope
 
     const highlight_person = make_person_highlighter(query);
 
-    const objs = persons.map(person => {
+    const objs = persons.map((person) => {
         const name = highlight_person(person);
         const description = prefix + ' ' + name;
         const terms = [{
@@ -340,7 +340,7 @@ function get_topic_suggestions(last, operators) {
     topics = topics.slice(0, 300);
 
     if (guess !== '') {
-        topics = topics.filter(topic => common.phrase_match(guess, topic));
+        topics = topics.filter((topic) => common.phrase_match(guess, topic));
     }
 
     topics = topics.slice(0, 10);
@@ -351,7 +351,7 @@ function get_topic_suggestions(last, operators) {
     // care about case.
     topics.sort();
 
-    return topics.map(topic => {
+    return topics.map((topic) => {
         const topic_term = {operator: 'topic', operand: topic, negated: negated};
         const operators = suggest_operators.concat([topic_term]);
         return format_as_suggestion(operators);
@@ -382,7 +382,7 @@ function get_special_filter_suggestions(last, operators, suggestions) {
     // Negating suggestions on is_search_operand_negated is required for
     // suggesting negated operators.
     if (last.negated || is_search_operand_negated) {
-        suggestions = suggestions.map(suggestion => ({
+        suggestions = suggestions.map((suggestion) => ({
             search_string: '-' + suggestion.search_string,
             description: 'exclude ' + suggestion.description,
             invalid: suggestion.invalid,
@@ -390,7 +390,7 @@ function get_special_filter_suggestions(last, operators, suggestions) {
     }
 
     const last_string = Filter.unparse([last]).toLowerCase();
-    suggestions = suggestions.filter(s => {
+    suggestions = suggestions.filter((s) => {
         if (match_criteria(operators, s.invalid)) {
             return false;
         }
@@ -565,9 +565,9 @@ function get_operator_suggestions(last) {
     }
 
     let choices = ['stream', 'topic', 'pm-with', 'sender', 'near', 'from', 'group-pm-with'];
-    choices = choices.filter(choice => common.phrase_match(last_operand, choice));
+    choices = choices.filter((choice) => common.phrase_match(last_operand, choice));
 
-    return choices.map(choice => {
+    return choices.map((choice) => {
         const op = [{operator: choice, operand: '', negated: negated}];
         return format_as_suggestion(op);
     });
@@ -743,7 +743,7 @@ exports.finalize_search_result = function (result) {
         lookup_table.set(obj.search_string, obj);
     }
 
-    const strings = result.map(obj => obj.search_string);
+    const strings = result.map((obj) => obj.search_string);
     return {
         strings: strings,
         lookup_table: lookup_table,
diff --git a/static/js/search_util.js b/static/js/search_util.js
index 89e6661fce..721d704012 100644
--- a/static/js/search_util.js
+++ b/static/js/search_util.js
@@ -17,7 +17,7 @@ exports.vanilla_match = function (opts) {
         This is case insensitive.
     */
     const val = opts.val.toLowerCase();
-    return opts.search_terms.some(term => val.includes(term));
+    return opts.search_terms.some((term) => val.includes(term));
 };
 
 window.search_util = exports;
diff --git a/static/js/server_events.js b/static/js/server_events.js
index a62598960a..6e2b7555d8 100644
--- a/static/js/server_events.js
+++ b/static/js/server_events.js
@@ -99,7 +99,7 @@ function get_events_success(events) {
             if (messages.length > 0) {
                 messages.forEach(message_store.set_message_booleans);
 
-                const sent_by_this_client = messages.some(msg =>
+                const sent_by_this_client = messages.some((msg) =>
                     sent_messages.messages.has(msg.local_id)
                 );
                 // If some message in this batch of events was sent by this
diff --git a/static/js/settings_bots.js b/static/js/settings_bots.js
index 4ca9cf9dab..6696732f0b 100644
--- a/static/js/settings_bots.js
+++ b/static/js/settings_bots.js
@@ -64,7 +64,7 @@ function is_local_part(value, element) {
 }
 
 exports.type_id_to_string = function (type_id) {
-    return page_params.bot_types.find(bot_type => bot_type.type_id === type_id).name;
+    return page_params.bot_types.find((bot_type) => bot_type.type_id === type_id).name;
 };
 
 exports.render_bots = function () {
@@ -392,7 +392,7 @@ exports.set_up = function () {
         const bot_id = parseInt(li.find('.bot_info').attr('data-user-id'), 10);
         const bot = bot_data.get(bot_id);
         const user_ids = people.get_active_human_ids();
-        const users_list = user_ids.map(user_id => ({
+        const users_list = user_ids.map((user_id) => ({
             name: people.get_full_name(user_id),
             value: user_id.toString(),
         }));
diff --git a/static/js/settings_config.js b/static/js/settings_config.js
index 92dbb1a575..daee61a0eb 100644
--- a/static/js/settings_config.js
+++ b/static/js/settings_config.js
@@ -192,7 +192,7 @@ exports.user_role_values = {
 };
 
 const user_role_array = Object.values(exports.user_role_values);
-exports.user_role_map = new Map(user_role_array.map(role => [role.code, role.description]));
+exports.user_role_map = new Map(user_role_array.map((role) => [role.code, role.description]));
 
 // NOTIFICATIONS
 
diff --git a/static/js/settings_org.js b/static/js/settings_org.js
index 92d42bbb77..122aac1917 100644
--- a/static/js/settings_org.js
+++ b/static/js/settings_org.js
@@ -43,7 +43,7 @@ exports.maybe_disable_widgets = function () {
 };
 
 exports.get_sorted_options_list = function (option_values_object) {
-    const options_list = Object.keys(option_values_object).map(key => ({
+    const options_list = Object.keys(option_values_object).map((key) => ({
         ...option_values_object[key],
         key: key,
     }));
@@ -264,7 +264,7 @@ exports.populate_realm_domains = function (realm_domains) {
     }
 
     const domains_list = realm_domains.map(
-        realm_domain => realm_domain.allow_subdomains ? "*." + realm_domain.domain : realm_domain.domain
+        (realm_domain) => realm_domain.allow_subdomains ? "*." + realm_domain.domain : realm_domain.domain
     );
     let domains = domains_list.join(', ');
     if (domains.length === 0) {
@@ -547,7 +547,7 @@ exports.signup_notifications_stream_widget = null;
 exports.init_dropdown_widgets = () => {
     const streams = stream_data.get_streams_for_settings_page();
     const notification_stream_options = {
-        data: streams.map(x => {
+        data: streams.map((x) => {
             const item = {
                 name: x.name,
                 value: x.stream_id.toString(),
@@ -575,7 +575,7 @@ exports.init_dropdown_widgets = () => {
                       notification_stream_options));
     exports.default_code_language_widget = dropdown_list_widget({
         widget_name: 'realm_default_code_block_language',
-        data: Object.keys(pygments_data.langs).map(x => {
+        data: Object.keys(pygments_data.langs).map((x) => {
             return {
                 name: x,
                 value: x,
diff --git a/static/js/settings_user_groups.js b/static/js/settings_user_groups.js
index 0d1e7207bc..d5575e1a50 100644
--- a/static/js/settings_user_groups.js
+++ b/static/js/settings_user_groups.js
@@ -198,7 +198,7 @@ exports.populate_user_groups = function () {
                                               except_class);
             if ($(event.relatedTarget).closest('#user-groups #' + data.id).length) {
                 return blur_exceptions.some(
-                    class_name => $(event.relatedTarget).closest(class_name).length
+                    (class_name) => $(event.relatedTarget).closest(class_name).length
                 );
             }
             return false;
diff --git a/static/js/settings_users.js b/static/js/settings_users.js
index 0ce894ec44..51e3bf8dc9 100644
--- a/static/js/settings_users.js
+++ b/static/js/settings_users.js
@@ -458,7 +458,7 @@ function open_bot_form(person) {
     const owner_id = bot_data.get(person.user_id).owner_id;
 
     const user_ids = people.get_active_human_ids();
-    const users_list = user_ids.map(user_id => ({
+    const users_list = user_ids.map((user_id) => ({
         name: people.get_full_name(user_id),
         value: user_id.toString(),
     }));
diff --git a/static/js/stream_create.js b/static/js/stream_create.js
index 2fe05ecca7..e75ad7db80 100644
--- a/static/js/stream_create.js
+++ b/static/js/stream_create.js
@@ -126,7 +126,7 @@ function update_announce_stream_state() {
 }
 
 function get_principals() {
-    return Array.from($("#stream_creation_form input:checkbox[name=user]:checked"), elem => {
+    return Array.from($("#stream_creation_form input:checkbox[name=user]:checked"), (elem) => {
         const label = $(elem).closest(".add-user-label");
         return parseInt(label.attr("data-user-id"), 10);
     });
diff --git a/static/js/stream_data.js b/static/js/stream_data.js
index 7e6629aa86..7563bbf180 100644
--- a/static/js/stream_data.js
+++ b/static/js/stream_data.js
@@ -167,7 +167,7 @@ exports.is_subscriber_subset = function (sub1, sub2) {
     if (sub1.subscribers && sub2.subscribers) {
         const sub2_set = sub2.subscribers;
 
-        return Array.from(sub1.subscribers.keys()).every(key => sub2_set.has(key));
+        return Array.from(sub1.subscribers.keys()).every((key) => sub2_set.has(key));
     }
 
     return false;
@@ -319,9 +319,10 @@ exports.delete_sub = function (stream_id) {
 exports.get_non_default_stream_names = function () {
     let subs = Array.from(stream_info.values());
     subs = subs.filter(
-        sub => !exports.is_default_stream_id(sub.stream_id) && (sub.subscribed || !sub.invite_only)
+        (sub) =>
+            !exports.is_default_stream_id(sub.stream_id) && (sub.subscribed || !sub.invite_only)
     );
-    const names = subs.map(sub => sub.name);
+    const names = subs.map((sub) => sub.name);
     return names;
 };
 
@@ -342,7 +343,7 @@ exports.get_updated_unsorted_subs = function () {
 
     // We don't display unsubscribed streams to guest users.
     if (page_params.is_guest) {
-        all_subs = all_subs.filter(sub => sub.subscribed);
+        all_subs = all_subs.filter((sub) => sub.subscribed);
     }
 
     return all_subs;
@@ -361,7 +362,7 @@ exports.unsubscribed_subs = function () {
 };
 
 exports.subscribed_streams = function () {
-    return exports.subscribed_subs().map(sub => sub.name);
+    return exports.subscribed_subs().map((sub) => sub.name);
 };
 
 exports.get_invite_stream_data = function () {
@@ -393,7 +394,7 @@ exports.get_invite_stream_data = function () {
 };
 
 exports.get_colors = function () {
-    return exports.subscribed_subs().map(sub => sub.color);
+    return exports.subscribed_subs().map((sub) => sub.color);
 };
 
 exports.update_subscribers_count = function (sub) {
@@ -510,12 +511,12 @@ exports.update_calculated_fields = function (sub) {
 };
 
 exports.all_subscribed_streams_are_in_home_view = function () {
-    return exports.subscribed_subs().every(sub => !sub.is_muted);
+    return exports.subscribed_subs().every((sub) => !sub.is_muted);
 };
 
 exports.home_view_stream_names = function () {
-    const home_view_subs = exports.subscribed_subs().filter(sub => !sub.is_muted);
-    return home_view_subs.map(sub => sub.name);
+    const home_view_subs = exports.subscribed_subs().filter((sub) => !sub.is_muted);
+    return home_view_subs.map((sub) => sub.name);
 };
 
 exports.canonicalized_name = function (stream_name) {
diff --git a/static/js/stream_popover.js b/static/js/stream_popover.js
index ef8746a70e..c96a531623 100644
--- a/static/js/stream_popover.js
+++ b/static/js/stream_popover.js
@@ -273,7 +273,7 @@ function build_move_topic_to_stream_popover(e, current_stream_id, topic_name) {
     // likely will make it possible to move messages to/from private
     // streams in the future.
     const available_streams = stream_data.subscribed_subs()
-        .filter(s => s.stream_id !== current_stream_id);
+        .filter((s) => s.stream_id !== current_stream_id);
     const current_stream_name = stream_data.maybe_get_stream_name(current_stream_id);
     const args = {
         available_streams, topic_name, current_stream_id, current_stream_name,
diff --git a/static/js/stream_sort.js b/static/js/stream_sort.js
index d25e6fdf41..95983c9d2c 100644
--- a/static/js/stream_sort.js
+++ b/static/js/stream_sort.js
@@ -16,13 +16,13 @@ function filter_streams_by_search(streams, search_term) {
     }
 
     let search_terms = search_term.toLowerCase().split(",");
-    search_terms = search_terms.map(s => s.trim());
+    search_terms = search_terms.map((s) => s.trim());
 
-    const filtered_streams = streams.filter(stream => search_terms.some(search_term => {
+    const filtered_streams = streams.filter((stream) => search_terms.some((search_term) => {
         const lower_stream_name = stream.toLowerCase();
         const cands = lower_stream_name.split(" ");
         cands.push(lower_stream_name);
-        return cands.some(name => name.startsWith(search_term));
+        return cands.some((name) => name.startsWith(search_term));
     }));
 
     return filtered_streams;
diff --git a/static/js/stream_topic_history.js b/static/js/stream_topic_history.js
index 31223b725e..9432924a43 100644
--- a/static/js/stream_topic_history.js
+++ b/static/js/stream_topic_history.js
@@ -184,7 +184,7 @@ exports.per_stream_history = function (stream_id) {
             return b.message_id - a.message_id;
         });
 
-        const names = recents.map(obj => obj.pretty_name);
+        const names = recents.map((obj) => obj.pretty_name);
 
         return names;
     };
diff --git a/static/js/submessage.js b/static/js/submessage.js
index df6eed6f3c..a6be77336b 100644
--- a/static/js/submessage.js
+++ b/static/js/submessage.js
@@ -15,7 +15,7 @@ exports.get_message_events = function (message) {
         return parseInt(m1.id, 10) - parseInt(m2.id, 10);
     });
 
-    const events = message.submessages.map(obj => ({
+    const events = message.submessages.map((obj) => ({
         sender_id: obj.sender_id,
         data: JSON.parse(obj.content),
     }));
@@ -90,7 +90,7 @@ exports.update_message = function (submsg) {
         message.submessages = [];
     }
 
-    const existing = message.submessages.find(sm => sm.id === submsg.id);
+    const existing = message.submessages.find((sm) => sm.id === submsg.id);
 
     if (existing !== undefined) {
         blueslip.warn("Got submessage multiple times: " + submsg.id);
diff --git a/static/js/templates.js b/static/js/templates.js
index 060c975fe2..8622030bbd 100644
--- a/static/js/templates.js
+++ b/static/js/templates.js
@@ -85,13 +85,13 @@ Handlebars.registerHelper('tr', function (context, options) {
     //     1. `context` is very important. It can be `this` or an
     //        object or key of the current context.
     //     2. Use `__` instead of `{{` and `}}` to declare expressions
-    const result = i18n.t(options.fn(context).trim().split("\n").map(s => s.trim()).join(" "), context);
+    const result = i18n.t(options.fn(context).trim().split("\n").map((s) => s.trim()).join(" "), context);
     return new Handlebars.SafeString(result);
 });
 
 Handlebars.registerHelper(
     "rendered_markdown",
-    content => new Handlebars.SafeString(util.clean_user_content_links(content))
+    (content) => new Handlebars.SafeString(util.clean_user_content_links(content))
 );
 
 window.templates = exports;
diff --git a/static/js/topic_generator.js b/static/js/topic_generator.js
index ddd506b563..f6102166e4 100644
--- a/static/js/topic_generator.js
+++ b/static/js/topic_generator.js
@@ -193,7 +193,7 @@ exports.next_topic = function (streams, get_topics, has_unread_messages, curr_st
 exports.get_next_topic = function (curr_stream, curr_topic) {
     let my_streams = stream_sort.get_streams();
 
-    my_streams = my_streams.filter(stream_name => {
+    my_streams = my_streams.filter((stream_name) => {
         if (!stream_data.is_stream_muted_by_name(stream_name)) {
             return true;
         }
@@ -208,7 +208,7 @@ exports.get_next_topic = function (curr_stream, curr_topic) {
     function get_unmuted_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 => !muting.is_topic_muted(stream_id, topic));
+        topics = topics.filter((topic) => !muting.is_topic_muted(stream_id, topic));
         return topics;
     }
 
diff --git a/static/js/typeahead_helper.js b/static/js/typeahead_helper.js
index 74cb7a0c8e..1ce2089d49 100644
--- a/static/js/typeahead_helper.js
+++ b/static/js/typeahead_helper.js
@@ -8,7 +8,7 @@ const settings_data = require("./settings_data");
 // For example, "a,,b, " => ["a", "b"]
 exports.get_cleaned_pm_recipients = function (query_string) {
     let recipients = util.extract_pm_recipients(query_string);
-    recipients = recipients.filter(elem => elem.match(/\S/));
+    recipients = recipients.filter((elem) => elem.match(/\S/));
     return recipients;
 };
 
diff --git a/static/js/typing_data.js b/static/js/typing_data.js
index 679b710a36..6834c77e0f 100644
--- a/static/js/typing_data.js
+++ b/static/js/typing_data.js
@@ -32,7 +32,7 @@ exports.remove_typist = function (group, typist) {
         return false;
     }
 
-    current = current.filter(user_id => to_int(user_id) !== to_int(typist));
+    current = current.filter((user_id) => to_int(user_id) !== to_int(typist));
 
     typist_dct.set(key, current);
     return true;
diff --git a/static/js/ui_init.js b/static/js/ui_init.js
index ac97814411..6b6ddf6681 100644
--- a/static/js/ui_init.js
+++ b/static/js/ui_init.js
@@ -223,7 +223,7 @@ exports.initialize_kitchen_sink_stuff = function () {
                     render_end: event.msg_list.view._render_win_end,
                     selected_id_from_idx: messages[event.msg_list.selected_idx()].id,
                     msg_list_sorted: _.isEqual(
-                        messages.map(message => message.id),
+                        messages.map((message) => message.id),
                         _.chain(current_msg_list.all_messages()).pluck('id').clone().value().sort()
                     ),
                     found_in_dom: row_from_dom.length,
diff --git a/static/js/unread.js b/static/js/unread.js
index 94095185f0..dfeb9df0bf 100644
--- a/static/js/unread.js
+++ b/static/js/unread.js
@@ -273,9 +273,9 @@ exports.unread_topic_counter = (function () {
 
         let topic_names = Array.from(per_stream_bucketer.keys());
 
-        topic_names = topic_names.filter(topic_name => !topic_dict.has(topic_name));
+        topic_names = topic_names.filter((topic_name) => !topic_dict.has(topic_name));
 
-        const result = topic_names.map(topic_name => {
+        const result = topic_names.map((topic_name) => {
             const msgs = per_stream_bucketer.get_bucket(topic_name);
 
             return {
@@ -384,11 +384,11 @@ exports.message_unread = function (message) {
 };
 
 exports.get_unread_message_ids = function (message_ids) {
-    return message_ids.filter(message_id => unread_messages.has(message_id));
+    return message_ids.filter((message_id) => unread_messages.has(message_id));
 };
 
 exports.get_unread_messages = function (messages) {
-    return messages.filter(message => unread_messages.has(message.id));
+    return messages.filter((message) => unread_messages.has(message.id));
 };
 
 exports.update_unread_topics = function (msg, event) {
diff --git a/static/js/upload.js b/static/js/upload.js
index 8e9830e020..8ac948acf1 100644
--- a/static/js/upload.js
+++ b/static/js/upload.js
@@ -221,7 +221,7 @@ exports.setup_upload = function (config) {
 
     uppy.on('complete', () => {
         let uploads_in_progress = false;
-        uppy.getFiles().forEach(file => {
+        uppy.getFiles().forEach((file) => {
             if (file.progress.uploadComplete) {
                 // The uploaded files should be removed since uppy don't allow files in the store
                 // to be re-uploaded again.
diff --git a/static/js/user_pill.js b/static/js/user_pill.js
index 34357914a0..26943d1725 100644
--- a/static/js/user_pill.js
+++ b/static/js/user_pill.js
@@ -8,7 +8,7 @@ exports.create_item_from_email = function (email, current_items) {
 
     if (!user) {
         if (page_params.realm_is_zephyr_mirror_realm) {
-            const existing_emails = current_items.map(item => item.email);
+            const existing_emails = current_items.map((item) => item.email);
 
             if (existing_emails.includes(email)) {
                 return;
@@ -27,7 +27,7 @@ exports.create_item_from_email = function (email, current_items) {
         return;
     }
 
-    const existing_ids = current_items.map(item => item.user_id);
+    const existing_ids = current_items.map((item) => item.user_id);
 
     if (existing_ids.includes(user.user_id)) {
         return;
@@ -67,7 +67,7 @@ exports.append_person = function (opts) {
 
 exports.get_user_ids = function (pill_widget) {
     const items = pill_widget.items();
-    let user_ids = items.map(item => item.user_id);
+    let user_ids = items.map((item) => item.user_id);
     user_ids = user_ids.filter(Boolean); // be defensive about undefined users
 
     return user_ids;
@@ -81,7 +81,7 @@ exports.has_unconverted_data = function (pill_widget) {
     }
 
     const items = pill_widget.items();
-    const has_unknown_items = items.some(item => item.user_id === undefined);
+    const has_unknown_items = items.some((item) => item.user_id === undefined);
 
     return has_unknown_items;
 };
@@ -93,7 +93,7 @@ exports.typeahead_source = function (pill_widget) {
 
 exports.filter_taken_users = function (items, pill_widget) {
     const taken_user_ids = exports.get_user_ids(pill_widget);
-    items = items.filter(item => !taken_user_ids.includes(item.user_id));
+    items = items.filter((item) => !taken_user_ids.includes(item.user_id));
     return items;
 };
 
diff --git a/static/js/util.js b/static/js/util.js
index 1cb1978d56..21ea630522 100644
--- a/static/js/util.js
+++ b/static/js/util.js
@@ -68,7 +68,7 @@ exports.is_pm_recipient = function (user_id, message) {
 };
 
 exports.extract_pm_recipients = function (recipients) {
-    return recipients.split(/\s*[,;]\s*/).filter(recipient => recipient.trim() !== "");
+    return recipients.split(/\s*[,;]\s*/).filter((recipient) => recipient.trim() !== "");
 };
 
 exports.same_recipient = function util_same_recipient(a, b) {
@@ -102,9 +102,9 @@ exports.normalize_recipients = function (recipients) {
     // Converts a string listing emails of message recipients
     // into a canonical formatting: emails sorted ASCIIbetically
     // with exactly one comma and no spaces between each.
-    recipients = recipients.split(',').map(s => s.trim());
-    recipients = recipients.map(s => s.toLowerCase());
-    recipients = recipients.filter(s => s.length > 0);
+    recipients = recipients.split(',').map((s) => s.trim());
+    recipients = recipients.map((s) => s.toLowerCase());
+    recipients = recipients.filter((s) => s.length > 0);
     recipients.sort();
     return recipients.join(',');
 };
diff --git a/static/js/vdom.js b/static/js/vdom.js
index 6350f45b0e..0e79a8aea0 100644
--- a/static/js/vdom.js
+++ b/static/js/vdom.js
@@ -37,7 +37,7 @@ exports.render_tag = (tag) => {
     */
     const opts = tag.opts;
     const tag_name = tag.tag_name;
-    const attr_str = opts.attrs.map(attr => ' ' + attr[0] + '="' + _.escape(attr[1]) + '"').join('');
+    const attr_str = opts.attrs.map((attr) => ' ' + attr[0] + '="' + _.escape(attr[1]) + '"').join('');
 
     const start_tag = '<' + tag_name + attr_str + '>';
     const end_tag = '</' + tag_name + '>';
@@ -47,7 +47,7 @@ exports.render_tag = (tag) => {
         return;
     }
 
-    const innards = opts.keyed_nodes.map(node => node.render()).join('\n');
+    const innards = opts.keyed_nodes.map((node) => node.render()).join('\n');
     return start_tag + '\n' + innards + '\n' + end_tag;
 };
 
diff --git a/static/shared/js/typeahead.js b/static/shared/js/typeahead.js
index 1e2d95b59d..3667a79bc9 100644
--- a/static/shared/js/typeahead.js
+++ b/static/shared/js/typeahead.js
@@ -75,7 +75,7 @@ function query_matches_string(query, source_str, split_char) {
 // account, there might be 2 attrs: their full name and their email.
 // * split_char is the separator for this syntax (e.g. ' ').
 export function query_matches_source_attrs(query, source, match_attrs, split_char) {
-    return match_attrs.some(attr => {
+    return match_attrs.some((attr) => {
         const source_str = source[attr].toLowerCase();
         return query_matches_string(query, source_str, split_char);
     });
@@ -151,7 +151,7 @@ export function sort_emojis(objs, query) {
 
     function decent_match(name) {
         const pieces = name.toLowerCase().split('_');
-        return pieces.some(piece => piece.startsWith(lowerQuery));
+        return pieces.some((piece) => piece.startsWith(lowerQuery));
     }
 
     const popular_set = new Set(popular_emojis);
@@ -162,7 +162,7 @@ export function sort_emojis(objs, query) {
     }
 
     const popular_emoji_matches = objs.filter(is_popular);
-    const others = objs.filter(obj => !is_popular(obj));
+    const others = objs.filter((obj) => !is_popular(obj));
 
     const triage_results = triage(
         query,