From 16ea89ad89910f4bdcf0dd9771deb4b52b03cb35 Mon Sep 17 00:00:00 2001
From: Anders Kaseorg <anders@zulipchat.com>
Date: Fri, 1 Nov 2019 16:06:25 -0700
Subject: [PATCH] js: Automatically convert var to let and const in remaining
 files.

This commit was automatically generated by `tools/lint --only=eslint
--fix`, except for the `.eslintrc.json` change itself.

Signed-off-by: Anders Kaseorg <anders@zulipchat.com>
---
 .eslintrc.json             |  10 +++
 static/js/buddy_data.js    |   4 +-
 static/js/condense.js      |  50 ++++++------
 static/js/message_edit.js  | 156 ++++++++++++++++++-------------------
 static/js/notifications.js | 106 ++++++++++++-------------
 static/js/tab_bar.js       |  40 +++++-----
 static/js/upload.js        |  42 +++++-----
 7 files changed, 209 insertions(+), 199 deletions(-)

diff --git a/.eslintrc.json b/.eslintrc.json
index 142e4c6366..e844682ccc 100644
--- a/.eslintrc.json
+++ b/.eslintrc.json
@@ -367,6 +367,7 @@
         // Updated regex expressions are currently being tested in casper
         // files and will decide about a potential future enforcement of this rule.
         "no-useless-escape": "off",
+        "no-var": "error",
         "space-unary-ops": "error",
         "no-whitespace-before-property": "error",
         "no-with": "error",
@@ -411,6 +412,15 @@
         "yoda": "error"
     },
     "overrides": [
+        {
+            "files": [
+                "frontend_tests/casper_tests/*.js",
+                "frontend_tests/casper_lib/*.js"
+            ],
+            "rules": {
+                "no-var": "off" // PhantomJS doesn’t support let, const
+            }
+        },
         {
             "files": ["**/*.ts"],
             "parser": "@typescript-eslint/parser",
diff --git a/static/js/buddy_data.js b/static/js/buddy_data.js
index c4c7358d73..ab20c0d723 100644
--- a/static/js/buddy_data.js
+++ b/static/js/buddy_data.js
@@ -202,7 +202,7 @@ function get_last_seen(active_status, last_seen) {
         return last_seen;
     }
 
-    var last_seen_text = i18n.t('Last active: __last_seen__', {last_seen: last_seen});
+    const last_seen_text = i18n.t('Last active: __last_seen__', {last_seen: last_seen});
     return last_seen_text;
 }
 
@@ -226,7 +226,7 @@ exports.get_title_data = function (user_ids_string, is_group) {
             person.bot_owner_full_name = people.get_person_from_user_id(
                 person.bot_owner_id).full_name;
 
-            var bot_owner_name = i18n.t('Owner: __name__', {name: person.bot_owner_full_name});
+            const bot_owner_name = i18n.t('Owner: __name__', {name: person.bot_owner_full_name});
 
             return {
                 first_line: person.full_name,
diff --git a/static/js/condense.js b/static/js/condense.js
index 34a75347b7..8605e54471 100644
--- a/static/js/condense.js
+++ b/static/js/condense.js
@@ -10,9 +10,9 @@ This library implements two related, similar concepts:
 
 */
 
-var Dict = require('./dict').Dict;
+const Dict = require('./dict').Dict;
 
-var _message_content_height_cache = new Dict();
+let _message_content_height_cache = new Dict();
 
 function show_more_link(row) {
     row.find(".message_condenser").hide();
@@ -25,13 +25,13 @@ function show_condense_link(row) {
 }
 
 function condense_row(row) {
-    var content = row.find(".message_content");
+    const content = row.find(".message_content");
     content.addClass("condensed");
     show_more_link(row);
 }
 
 function uncondense_row(row) {
-    var content = row.find(".message_content");
+    const content = row.find(".message_content");
     content.removeClass("condensed");
     show_condense_link(row);
 }
@@ -39,12 +39,12 @@ function uncondense_row(row) {
 exports.uncollapse = function (row) {
     // Uncollapse a message, restoring the condensed message [More] or
     // [Condense] link if necessary.
-    var message = current_msg_list.get(rows.id(row));
+    const message = current_msg_list.get(rows.id(row));
     message.collapsed = false;
     message_flags.save_uncollapsed(message);
 
-    var process_row = function process_row(row) {
-        var content = row.find(".message_content");
+    const process_row = function process_row(row) {
+        const content = row.find(".message_content");
         content.removeClass("collapsed");
 
         if (message.condensed === true) {
@@ -65,7 +65,7 @@ exports.uncollapse = function (row) {
     };
 
     // We also need to collapse this message in the home view
-    var home_row = home_msg_list.get_row(rows.id(row));
+    const home_row = home_msg_list.get_row(rows.id(row));
 
     process_row(row);
     process_row(home_row);
@@ -74,7 +74,7 @@ exports.uncollapse = function (row) {
 exports.collapse = function (row) {
     // Collapse a message, hiding the condensed message [More] or
     // [Condense] link if necessary.
-    var message = current_msg_list.get(rows.id(row));
+    const message = current_msg_list.get(rows.id(row));
     message.collapsed = true;
 
     if (message.locally_echoed) {
@@ -87,13 +87,13 @@ exports.collapse = function (row) {
 
     message_flags.save_collapsed(message);
 
-    var process_row = function process_row(row) {
+    const process_row = function process_row(row) {
         row.find(".message_content").addClass("collapsed");
         show_more_link(row);
     };
 
     // We also need to collapse this message in the home view
-    var home_row = home_msg_list.get_row(rows.id(row));
+    const home_row = home_msg_list.get_row(rows.id(row));
 
     process_row(row);
     process_row(home_row);
@@ -115,14 +115,14 @@ exports.toggle_collapse = function (message) {
     // * If the message is fully visible, either because it's too short to
     //   condense or because it's already uncondensed, collapse it
 
-    var row = current_msg_list.get_row(message.id);
+    const row = current_msg_list.get_row(message.id);
     if (!row) {
         return;
     }
 
-    var content = row.find(".message_content");
-    var is_condensable = content.hasClass("could-be-condensed");
-    var is_condensed = content.hasClass("condensed");
+    const content = row.find(".message_content");
+    const is_condensable = content.hasClass("could-be-condensed");
+    const is_condensed = content.hasClass("condensed");
     if (message.collapsed) {
         if (is_condensable) {
             message.condensed = true;
@@ -157,7 +157,7 @@ function get_message_height(elem, message_id) {
     }
 
     // shown to be ~2.5x faster than Node.getBoundingClientRect().
-    var height = elem.offsetHeight;
+    const height = elem.offsetHeight;
     _message_content_height_cache.set(message_id, height);
     return height;
 }
@@ -175,14 +175,14 @@ exports.show_message_expander = function (row) {
 };
 
 exports.condense_and_collapse = function (elems) {
-    var height_cutoff = message_viewport.height() * 0.65;
+    const height_cutoff = message_viewport.height() * 0.65;
 
     _.each(elems, function (elem) {
-        var content = $(elem).find(".message_content");
-        var message = current_msg_list.get(rows.id($(elem)));
+        const content = $(elem).find(".message_content");
+        const message = current_msg_list.get(rows.id($(elem)));
         if (content !== undefined && message !== undefined) {
-            var message_height = get_message_height(elem, message.id);
-            var long_message = message_height > height_cutoff;
+            const message_height = get_message_height(elem, message.id);
+            const long_message = message_height > height_cutoff;
             if (long_message) {
                 // All long messages are flagged as such.
                 content.addClass("could-be-condensed");
@@ -220,9 +220,9 @@ exports.initialize = function () {
     $("#home").on("click", ".message_expander", function () {
         // Expanding a message can mean either uncollapsing or
         // uncondensing it.
-        var row = $(this).closest(".message_row");
-        var message = current_msg_list.get(rows.id(row));
-        var content = row.find(".message_content");
+        const row = $(this).closest(".message_row");
+        const message = current_msg_list.get(rows.id(row));
+        const content = row.find(".message_content");
         if (message.collapsed) {
             // Uncollapse.
             exports.uncollapse(row);
@@ -236,7 +236,7 @@ exports.initialize = function () {
     });
 
     $("#home").on("click", ".message_condenser", function () {
-        var row = $(this).closest(".message_row");
+        const row = $(this).closest(".message_row");
         current_msg_list.get(rows.id(row)).condensed = true;
         condense_row(row);
     });
diff --git a/static/js/message_edit.js b/static/js/message_edit.js
index a6253d734c..2acbc4e700 100644
--- a/static/js/message_edit.js
+++ b/static/js/message_edit.js
@@ -1,12 +1,12 @@
-var render_message_edit_form = require('../templates/message_edit_form.hbs');
-var render_message_edit_history = require('../templates/message_edit_history.hbs');
-var render_topic_edit_form = require('../templates/topic_edit_form.hbs');
+const render_message_edit_form = require('../templates/message_edit_form.hbs');
+const render_message_edit_history = require('../templates/message_edit_history.hbs');
+const render_topic_edit_form = require('../templates/topic_edit_form.hbs');
 
-var currently_editing_messages = {};
-var currently_deleting_messages = [];
-var currently_echoing_messages = {};
+const currently_editing_messages = {};
+let currently_deleting_messages = [];
+const currently_echoing_messages = {};
 
-var editability_types = {
+const editability_types = {
     NO: 1,
     NO_LONGER: 2,
     // Note: TOPIC_ONLY does not include stream messages with no topic sent
@@ -21,7 +21,7 @@ var editability_types = {
 exports.editability_types = editability_types;
 
 function is_topic_editable(message, edit_limit_seconds_buffer) {
-    var now = new XDate();
+    const now = new XDate();
     edit_limit_seconds_buffer = edit_limit_seconds_buffer || 0;
 
     if (!page_params.realm_allow_message_editing) {
@@ -82,7 +82,7 @@ function get_editability(message, edit_limit_seconds_buffer) {
         return editability_types.NO;
     }
 
-    var now = new XDate();
+    const now = new XDate();
     if (page_params.realm_message_content_edit_limit_seconds + edit_limit_seconds_buffer +
         now.diffSeconds(message.timestamp * 1000) > 0 && message.sent_by_me) {
         return editability_types.FULL;
@@ -118,7 +118,7 @@ exports.get_deletability = function (message) {
     }
 
     if (page_params.realm_allow_message_deleting) {
-        var now = new XDate();
+        const now = new XDate();
         if (page_params.realm_message_content_delete_limit_seconds +
             now.diffSeconds(message.timestamp * 1000) > 0) {
             return true;
@@ -136,7 +136,7 @@ exports.update_message_topic_editing_pencil = function () {
 };
 
 exports.show_topic_edit_spinner = function (row) {
-    var spinner = row.find(".topic_edit_spinner");
+    const spinner = row.find(".topic_edit_spinner");
     loading.make_indicator(spinner);
     $(spinner).removeAttr("style");
     $(".topic_edit_save").hide();
@@ -144,14 +144,14 @@ exports.show_topic_edit_spinner = function (row) {
 };
 
 function handle_edit_keydown(from_topic_edited_only, e) {
-    var row;
-    var code = e.keyCode || e.which;
+    let row;
+    const code = e.keyCode || e.which;
 
     if ($(e.target).hasClass("message_edit_content") && code === 13) {
         // Pressing enter to save edits is coupled with enter to send
         if (composebox_typeahead.should_enter_send(e)) {
             row = $(".message_edit_content").filter(":focus").closest(".message_row");
-            var message_edit_save_button = row.find(".message_edit_save");
+            const message_edit_save_button = row.find(".message_edit_save");
             if (message_edit_save_button.attr('disabled') === "disabled") {
                 // In cases when the save button is disabled
                 // we need to disable save on pressing enter
@@ -179,8 +179,8 @@ function handle_edit_keydown(from_topic_edited_only, e) {
 }
 
 function timer_text(seconds_left) {
-    var minutes = Math.floor(seconds_left / 60);
-    var seconds = seconds_left % 60;
+    const minutes = Math.floor(seconds_left / 60);
+    const seconds = seconds_left % 60;
     if (minutes >= 1) {
         return i18n.t("__minutes__ min to edit", {minutes: minutes.toString()});
     } else if (seconds_left >= 10) {
@@ -192,10 +192,10 @@ function timer_text(seconds_left) {
 function edit_message(row, raw_content) {
     row.find(".message_reactions").hide();
     condense.hide_message_expander(row);
-    var content_top = row.find('.message_top_line')[0]
+    const content_top = row.find('.message_top_line')[0]
         .getBoundingClientRect().top;
 
-    var message = current_msg_list.get(rows.id(row));
+    const message = current_msg_list.get(rows.id(row));
 
     // We potentially got to this function by clicking a button that implied the
     // user would be able to edit their message.  Give a little bit of buffer in
@@ -205,18 +205,18 @@ function edit_message(row, raw_content) {
     // a buffer in case their computer is slow, or stalled for a second, etc
     // If you change this number also change edit_limit_buffer in
     // zerver.views.messages.update_message_backend
-    var seconds_left_buffer = 5;
-    var editability = get_editability(message, seconds_left_buffer);
-    var is_editable = editability === exports.editability_types.TOPIC_ONLY ||
+    const seconds_left_buffer = 5;
+    const editability = get_editability(message, seconds_left_buffer);
+    const is_editable = editability === exports.editability_types.TOPIC_ONLY ||
                        editability === exports.editability_types.FULL;
-    var max_file_upload_size = page_params.max_file_upload_size;
-    var file_upload_enabled = false;
+    const max_file_upload_size = page_params.max_file_upload_size;
+    let file_upload_enabled = false;
 
     if (max_file_upload_size > 0) {
         file_upload_enabled = true;
     }
 
-    var form = $(render_message_edit_form({
+    const form = $(render_message_edit_form({
         is_stream: message.type === 'stream',
         message_id: message.id,
         is_editable: is_editable,
@@ -228,7 +228,7 @@ function edit_message(row, raw_content) {
         minutes_to_edit: Math.floor(page_params.realm_message_content_edit_limit_seconds / 60),
     }));
 
-    var edit_obj = {form: form, raw_content: raw_content};
+    const edit_obj = {form: form, raw_content: raw_content};
     currently_editing_messages[message.id] = edit_obj;
     current_msg_list.show_edit_message(row, edit_obj);
 
@@ -236,11 +236,11 @@ function edit_message(row, raw_content) {
 
     upload.feature_check($('#attach_files_' + rows.id(row)));
 
-    var message_edit_content = row.find('textarea.message_edit_content');
-    var message_edit_topic = row.find('input.message_edit_topic');
-    var message_edit_topic_propagate = row.find('select.message_edit_topic_propagate');
-    var message_edit_countdown_timer = row.find('.message_edit_countdown_timer');
-    var copy_message = row.find('.copy_message');
+    const message_edit_content = row.find('textarea.message_edit_content');
+    const message_edit_topic = row.find('input.message_edit_topic');
+    const message_edit_topic_propagate = row.find('select.message_edit_topic_propagate');
+    const message_edit_countdown_timer = row.find('.message_edit_countdown_timer');
+    const copy_message = row.find('.copy_message');
 
     if (editability === editability_types.NO) {
         message_edit_content.prop("readonly", "readonly");
@@ -261,8 +261,8 @@ function edit_message(row, raw_content) {
         new ClipboardJS(copy_message[0]);
     } else if (editability === editability_types.FULL) {
         copy_message.remove();
-        var edit_id = "#message_edit_content_" + rows.id(row);
-        var listeners = resize.watch_manual_resize(edit_id);
+        const edit_id = "#message_edit_content_" + rows.id(row);
+        const listeners = resize.watch_manual_resize(edit_id);
         if (listeners) {
             currently_editing_messages[rows.id(row)].listeners = listeners;
         }
@@ -294,16 +294,16 @@ function edit_message(row, raw_content) {
         // Give them at least 10 seconds.
         // If you change this number also change edit_limit_buffer in
         // zerver.views.messages.update_message_backend
-        var min_seconds_to_edit = 10;
-        var now = new XDate();
-        var seconds_left = page_params.realm_message_content_edit_limit_seconds +
+        const min_seconds_to_edit = 10;
+        const now = new XDate();
+        let seconds_left = page_params.realm_message_content_edit_limit_seconds +
             now.diffSeconds(message.timestamp * 1000);
         seconds_left = Math.floor(Math.max(seconds_left, min_seconds_to_edit));
 
         // I believe this needs to be defined outside the countdown_timer, since
         // row just refers to something like the currently selected message, and
         // can change out from under us
-        var message_edit_save = row.find('button.message_edit_save');
+        const message_edit_save = row.find('button.message_edit_save');
         // Do this right away, rather than waiting for the timer to do its first update,
         // since otherwise there is a noticeable lag
         message_edit_countdown_timer.text(timer_text(seconds_left));
@@ -338,23 +338,23 @@ function edit_message(row, raw_content) {
     } else {
         message_edit_content.focus();
         // Put cursor at end of input.
-        var contents = message_edit_content.val();
+        const contents = message_edit_content.val();
         message_edit_content.val('');
         message_edit_content.val(contents);
     }
 
     // Scroll to keep the top of the message content text in the same
     // place visually, adjusting for border and padding.
-    var edit_top = message_edit_content[0].getBoundingClientRect().top;
-    var scroll_by = edit_top - content_top + 5 - 14;
+    const edit_top = message_edit_content[0].getBoundingClientRect().top;
+    const scroll_by = edit_top - content_top + 5 - 14;
 
     edit_obj.scrolled_by = scroll_by;
     message_viewport.scrollTop(message_viewport.scrollTop() + scroll_by);
 
     if (feature_flags.propagate_topic_edits && !message.locally_echoed) {
-        var original_topic = util.get_message_topic(message);
+        const original_topic = util.get_message_topic(message);
         message_edit_topic.keyup(function () {
-            var new_topic = message_edit_topic.val();
+            const new_topic = message_edit_topic.val();
             message_edit_topic_propagate.toggle(new_topic !== original_topic && new_topic !== "");
         });
     }
@@ -362,8 +362,8 @@ function edit_message(row, raw_content) {
 
 function start_edit_maintaining_scroll(row, content) {
     edit_message(row, content);
-    var row_bottom = row.height() + row.offset().top;
-    var composebox_top = $("#compose").offset().top;
+    const row_bottom = row.height() + row.offset().top;
+    const composebox_top = $("#compose").offset().top;
     if (row_bottom > composebox_top) {
         message_viewport.scrollTop(message_viewport.scrollTop() + row_bottom - composebox_top);
     }
@@ -384,7 +384,7 @@ function start_edit_with_content(row, content, edit_box_open_callback) {
 }
 
 exports.start = function (row, edit_box_open_callback) {
-    var message = current_msg_list.get(rows.id(row));
+    const message = current_msg_list.get(rows.id(row));
     if (message === undefined) {
         blueslip.error("Couldn't find message ID for edit " + rows.id(row));
         return;
@@ -395,7 +395,7 @@ exports.start = function (row, edit_box_open_callback) {
         return;
     }
 
-    var msg_list = current_msg_list;
+    const msg_list = current_msg_list;
     channel.get({
         url: '/json/messages/' + message.id,
         idempotent: true,
@@ -409,12 +409,12 @@ exports.start = function (row, edit_box_open_callback) {
 };
 
 exports.start_topic_edit = function (recipient_row) {
-    var form = $(render_topic_edit_form());
+    const form = $(render_topic_edit_form());
     current_msg_list.show_edit_topic(recipient_row, form);
     form.keydown(_.partial(handle_edit_keydown, true));
-    var msg_id = rows.id_for_recipient_row(recipient_row);
-    var message = current_msg_list.get(msg_id);
-    var topic = util.get_message_topic(message);
+    const msg_id = rows.id_for_recipient_row(recipient_row);
+    const message = current_msg_list.get(msg_id);
+    let topic = util.get_message_topic(message);
     if (topic === compose.empty_topic_placeholder()) {
         topic = '';
     }
@@ -426,15 +426,15 @@ exports.is_editing = function (id) {
 };
 
 exports.end = function (row) {
-    var message = current_msg_list.get(rows.id(row));
+    const message = current_msg_list.get(rows.id(row));
     if (message !== undefined &&
         currently_editing_messages[message.id] !== undefined) {
-        var scroll_by = currently_editing_messages[message.id].scrolled_by;
+        const scroll_by = currently_editing_messages[message.id].scrolled_by;
         message_viewport.scrollTop(message_viewport.scrollTop() - scroll_by);
 
         // Clean up resize event listeners
-        var listeners = currently_editing_messages[message.id].listeners;
-        var edit_box = document.querySelector("#message_edit_content_" + message.id);
+        const listeners = currently_editing_messages[message.id].listeners;
+        const edit_box = document.querySelector("#message_edit_content_" + message.id);
         if (listeners !== undefined) {
             // Event listeners to cleanup are only set in some edit types
             edit_box.removeEventListener("mousedown", listeners[0]);
@@ -456,22 +456,22 @@ exports.end = function (row) {
 };
 
 exports.save = function (row, from_topic_edited_only) {
-    var msg_list = current_msg_list;
-    var message_id;
+    const msg_list = current_msg_list;
+    let message_id;
 
     if (row.hasClass('recipient_row')) {
         message_id = rows.id_for_recipient_row(row);
     } else {
         message_id = rows.id(row);
     }
-    var message = current_msg_list.get(message_id);
-    var changed = false;
-    var edit_locally_echoed = false;
+    const message = current_msg_list.get(message_id);
+    let changed = false;
+    let edit_locally_echoed = false;
 
-    var new_content = row.find(".message_edit_content").val();
-    var topic_changed = false;
-    var new_topic;
-    var old_topic = util.get_message_topic(message);
+    const new_content = row.find(".message_edit_content").val();
+    let topic_changed = false;
+    let new_topic;
+    const old_topic = util.get_message_topic(message);
 
     if (message.type === "stream") {
         if (from_topic_edited_only) {
@@ -495,11 +495,11 @@ exports.save = function (row, from_topic_edited_only) {
         return;
     }
 
-    var request = {message_id: message.id};
+    const request = {message_id: message.id};
     if (topic_changed) {
         util.set_message_topic(request, new_topic);
         if (feature_flags.propagate_topic_edits) {
-            var selected_topic_propagation = row.find("select.message_edit_topic_propagate").val() || "change_later";
+            const selected_topic_propagation = row.find("select.message_edit_topic_propagate").val() || "change_later";
             request.propagate_mode = selected_topic_propagation;
         }
         changed = true;
@@ -556,7 +556,7 @@ exports.save = function (row, from_topic_edited_only) {
         url: '/json/messages/' + message.id,
         data: request,
         success: function () {
-            var spinner = row.find(".topic_edit_spinner");
+            const spinner = row.find(".topic_edit_spinner");
             loading.destroy_indicator(spinner);
 
             if (edit_locally_echoed) {
@@ -569,8 +569,8 @@ exports.save = function (row, from_topic_edited_only) {
                 message_id = rows.id(row);
 
                 if (edit_locally_echoed) {
-                    var echoed_message = message_store.get(message_id);
-                    var echo_data = currently_echoing_messages[message_id];
+                    const echoed_message = message_store.get(message_id);
+                    const echo_data = currently_echoing_messages[message_id];
 
                     delete echoed_message.local_edit_timestamp;
                     delete currently_echoing_messages[message_id];
@@ -591,7 +591,7 @@ exports.save = function (row, from_topic_edited_only) {
                     }
                 }
 
-                var message = channel.xhr_error_message(i18n.t("Error saving edit"), xhr);
+                const message = channel.xhr_error_message(i18n.t("Error saving edit"), xhr);
                 row.find(".edit_error").text(message).show();
             }
         },
@@ -606,7 +606,7 @@ exports.maybe_show_edit = function (row, id) {
 };
 
 exports.edit_last_sent_message = function () {
-    var msg = current_msg_list.get_last_message_sent_by_me();
+    const msg = current_msg_list.get_last_message_sent_by_me();
 
     if (!msg) {
         return;
@@ -617,12 +617,12 @@ exports.edit_last_sent_message = function () {
         return;
     }
 
-    var msg_editability_type = exports.get_editability(msg, 5);
+    const msg_editability_type = exports.get_editability(msg, 5);
     if (msg_editability_type !== editability_types.FULL) {
         return;
     }
 
-    var msg_row = current_msg_list.get_row(msg.id);
+    const msg_row = current_msg_list.get_row(msg.id);
     if (!msg_row) {
         // This should never happen, since we got the message above
         // from current_msg_list.
@@ -646,17 +646,17 @@ exports.show_history = function (message) {
         url: "/json/messages/" + message.id + "/history",
         data: {message_id: JSON.stringify(message.id)},
         success: function (data) {
-            var content_edit_history = [];
-            var prev_timestamp;
+            const content_edit_history = [];
+            let prev_timestamp;
             _.each(data.message_history, function (msg, index) {
                 // Format timestamp nicely for display
-                var timestamp = timerender.get_full_time(msg.timestamp);
-                var item = {
+                const timestamp = timerender.get_full_time(msg.timestamp);
+                const item = {
                     timestamp: moment(timestamp).format("h:mm A"),
                     display_date: moment(timestamp).format("MMMM D, YYYY"),
                 };
                 if (msg.user_id) {
-                    var person = people.get_person_from_user_id(msg.user_id);
+                    const person = people.get_person_from_user_id(msg.user_id);
                     item.edited_by = person.full_name;
                 }
 
@@ -702,7 +702,7 @@ function hide_delete_btn_show_spinner(deleting) {
     if (deleting) {
         $('do_delete_message_button').attr('disabled', 'disabled');
         $('#delete_message_modal > div.modal-footer > button').hide();
-        var delete_spinner = $("#do_delete_message_spinner");
+        const delete_spinner = $("#do_delete_message_spinner");
         loading.make_indicator(delete_spinner, { abs_positioned: true });
     } else {
         loading.destroy_indicator($("#do_delete_message_spinner"));
@@ -761,7 +761,7 @@ exports.delete_topic = function (stream_id, topic_name) {
 exports.handle_narrow_deactivated = function () {
     _.each(currently_editing_messages, function (elem, idx) {
         if (current_msg_list.get(idx) !== undefined) {
-            var row = current_msg_list.get_row(idx);
+            const row = current_msg_list.get_row(idx);
             current_msg_list.show_edit_message(row, elem);
         }
     });
diff --git a/static/js/notifications.js b/static/js/notifications.js
index 202561a36b..e174cd19ae 100644
--- a/static/js/notifications.js
+++ b/static/js/notifications.js
@@ -1,20 +1,20 @@
-var render_compose_notification = require('../templates/compose_notification.hbs');
-var render_notification = require('../templates/notification.hbs');
+const render_compose_notification = require('../templates/compose_notification.hbs');
+const render_notification = require('../templates/notification.hbs');
 
-var notice_memory = {};
+let notice_memory = {};
 
 // When you start Zulip, window_has_focus should be true, but it might not be the
 // case after a server-initiated reload.
-var window_has_focus = document.hasFocus && document.hasFocus();
+let window_has_focus = document.hasFocus && document.hasFocus();
 
-var supports_sound;
+let supports_sound;
 
-var unread_pms_favicon = '/static/images/favicon/favicon-pms.png';
-var current_favicon;
-var previous_favicon;
-var flashing = false;
+const unread_pms_favicon = '/static/images/favicon/favicon-pms.png';
+let current_favicon;
+let previous_favicon;
+let flashing = false;
 
-var notifications_api;
+let notifications_api;
 
 exports.set_notification_api = function (n) {
     notifications_api = n;
@@ -33,9 +33,9 @@ if (window.webkitNotifications) {
         },
         requestPermission: window.Notification.requestPermission,
         createNotification: function createNotification(icon, title, content, tag) {
-            var notification_object = new window.Notification(title, {icon: icon,
-                                                                      body: content,
-                                                                      tag: tag});
+            const notification_object = new window.Notification(title, {icon: icon,
+                                                                        body: content,
+                                                                        tag: tag});
             notification_object.show = function () {};
             notification_object.cancel = function () { notification_object.close(); };
             return notification_object;
@@ -79,7 +79,7 @@ exports.initialize = function () {
         window_has_focus = false;
     });
 
-    var audio = $("<audio>");
+    const audio = $("<audio>");
     if (audio[0].canPlayType === undefined) {
         supports_sound = false;
     } else {
@@ -87,7 +87,7 @@ exports.initialize = function () {
 
         $("#notifications-area").append(audio);
         audio.append($("<source>").attr("loop", "yes"));
-        var source = $("#notifications-area audio source");
+        const source = $("#notifications-area audio source");
 
         if (audio[0].canPlayType('audio/ogg; codecs="vorbis"')) {
             source.attr("type", "audio/ogg");
@@ -95,7 +95,7 @@ exports.initialize = function () {
             source.attr("type", "audio/mpeg");
         }
 
-        var audio_file_without_extension
+        const audio_file_without_extension
             = "/static/audio/notification_sounds/" + page_params.notification_sound;
         source.attr("src", get_audio_file_path(audio[0], audio_file_without_extension));
     }
@@ -104,9 +104,9 @@ exports.initialize = function () {
 function update_notification_sound_source() {
     // Simplified version of the source creation in `exports.initialize`, for
     // updating the source instead of creating it for the first time.
-    var audio = $("#notifications-area audio");
-    var source = $("#notifications-area audio source");
-    var audio_file_without_extension
+    const audio = $("#notifications-area audio");
+    const source = $("#notifications-area audio source");
+    const audio_file_without_extension
         = "/static/audio/notification_sounds/" + page_params.notification_sound;
     source.attr("src", get_audio_file_path(audio[0], audio_file_without_extension));
 
@@ -124,7 +124,7 @@ exports.permission_state = function () {
     return window.Notification.permission;
 };
 
-var new_message_count = 0;
+let new_message_count = 0;
 
 exports.update_title_count = function (count) {
     new_message_count = count;
@@ -133,9 +133,9 @@ exports.update_title_count = function (count) {
 
 exports.redraw_title = function () {
     // Update window title and favicon to reflect unread messages in current view
-    var n;
+    let n;
 
-    var new_title = (new_message_count ? "(" + new_message_count + ") " : "")
+    const new_title = (new_message_count ? "(" + new_message_count + ") " : "")
         + narrow.narrow_title + " - "
         + page_params.realm_name + " - "
         + "Zulip";
@@ -230,7 +230,7 @@ exports.window_has_focus = function () {
 };
 
 function in_browser_notify(message, title, content, raw_operators, opts) {
-    var notification_html = $(render_notification({
+    const notification_html = $(render_notification({
         gravatar_url: people.small_avatar_url(message),
         title: title,
         content: content,
@@ -254,7 +254,7 @@ function in_browser_notify(message, title, content, raw_operators, opts) {
 }
 
 exports.notify_above_composebox = function (note, link_class, link_msg_id, link_text) {
-    var notification_html = $(render_compose_notification({
+    const notification_html = $(render_compose_notification({
         note: note,
         link_class: link_class,
         link_msg_id: link_msg_id,
@@ -272,8 +272,8 @@ if (window.electron_bridge !== undefined) {
     // to narrow to the message being sent.
     window.electron_bridge.send_notification_reply_message_supported = true;
     window.electron_bridge.on_event('send_notification_reply_message', function (message_id, reply) {
-        var message = message_store.get(message_id);
-        var data = {
+        const message = message_store.get(message_id);
+        const data = {
             type: message.type,
             content: reply,
             to: message.type === 'private' ? message.reply_to : message.stream,
@@ -306,23 +306,23 @@ if (window.electron_bridge !== undefined) {
 }
 
 function process_notification(notification) {
-    var i;
-    var notification_object;
-    var key;
-    var content;
-    var other_recipients;
-    var message = notification.message;
-    var title = message.sender_full_name;
-    var msg_count = 1;
-    var notification_source;
-    var raw_operators = [];
-    var opts = {trigger: "notification click"};
+    let i;
+    let notification_object;
+    let key;
+    let content;
+    let other_recipients;
+    const message = notification.message;
+    let title = message.sender_full_name;
+    let msg_count = 1;
+    let notification_source;
+    let raw_operators = [];
+    const opts = {trigger: "notification click"};
     // Convert the content to plain text, replacing emoji with their alt text
     content = $('<div/>').html(message.content);
     ui.replace_emoji_with_text(content);
     content = content.text();
 
-    var topic = util.get_message_topic(message);
+    const topic = util.get_message_topic(message);
 
     if (message.is_me_message) {
         content = message.sender_full_name + content.slice(3);
@@ -398,7 +398,7 @@ function process_notification(notification) {
 
     // Firefox on Ubuntu claims to do webkitNotifications but its notifications are terrible
     if (notification.desktop_notify && /webkit/i.test(navigator.userAgent)) {
-        var icon_url = people.small_avatar_url(message);
+        const icon_url = people.small_avatar_url(message);
         notice_memory[key] = {
             obj: notifications_api.createNotification(icon_url, title, content, message.id),
             msg_count: msg_count,
@@ -597,7 +597,7 @@ function get_message_header(message) {
 }
 
 exports.get_local_notify_mix_reason = function (message) {
-    var row = current_msg_list.get_row(message.id);
+    const row = current_msg_list.get_row(message.id);
     if (row.length > 0) {
         // If our message is in the current message list, we do
         // not have a mix, so we are happy.
@@ -645,7 +645,7 @@ exports.notify_local_mixes = function (messages, need_user_to_scroll) {
             return;
         }
 
-        var reason = exports.get_local_notify_mix_reason(message);
+        let reason = exports.get_local_notify_mix_reason(message);
 
         if (!reason) {
             if (need_user_to_scroll) {
@@ -661,10 +661,10 @@ exports.notify_local_mixes = function (messages, need_user_to_scroll) {
             return;
         }
 
-        var link_msg_id = message.id;
-        var link_class = "compose_notification_narrow_by_topic";
-        var link_text = i18n.t("Narrow to __- message_recipient__",
-                               {message_recipient: get_message_header(message)});
+        const link_msg_id = message.id;
+        const link_class = "compose_notification_narrow_by_topic";
+        const link_text = i18n.t("Narrow to __- message_recipient__",
+                                 {message_recipient: get_message_header(message)});
 
         exports.notify_above_composebox(reason, link_class, link_msg_id, link_text);
     });
@@ -677,8 +677,8 @@ exports.notify_messages_outside_current_search = function (messages) {
         if (!people.is_current_user(message.sender_email)) {
             return;
         }
-        var link_text = i18n.t("Narrow to __- message_recipient__",
-                               {message_recipient: get_message_header(message)});
+        const link_text = i18n.t("Narrow to __- message_recipient__",
+                                 {message_recipient: get_message_header(message)});
         exports.notify_above_composebox(i18n.t("Sent! Your recent message is outside the current search."),
                                         "compose_notification_narrow_by_topic",
                                         message.id,
@@ -693,14 +693,14 @@ exports.clear_compose_notifications = function () {
 };
 
 exports.reify_message_id = function (opts) {
-    var old_id = opts.old_id;
-    var new_id = opts.new_id;
+    const old_id = opts.old_id;
+    const new_id = opts.new_id;
 
     // If a message ID that we're currently storing (as a link) has changed,
     // update that link as well
     _.each($('#out-of-view-notification a'), function (e) {
-        var elem = $(e);
-        var message_id = elem.data('message-id');
+        const elem = $(e);
+        const message_id = elem.data('message-id');
 
         if (message_id === old_id) {
             elem.data('message-id', new_id);
@@ -710,13 +710,13 @@ exports.reify_message_id = function (opts) {
 
 exports.register_click_handlers = function () {
     $('#out-of-view-notification').on('click', '.compose_notification_narrow_by_topic', function (e) {
-        var message_id = $(e.currentTarget).data('message-id');
+        const message_id = $(e.currentTarget).data('message-id');
         narrow.by_topic(message_id, {trigger: 'compose_notification'});
         e.stopPropagation();
         e.preventDefault();
     });
     $('#out-of-view-notification').on('click', '.compose_notification_scroll_to_message', function (e) {
-        var message_id = $(e.currentTarget).data('message-id');
+        const message_id = $(e.currentTarget).data('message-id');
         current_msg_list.select_id(message_id);
         navigate.scroll_to_selected();
         e.stopPropagation();
diff --git a/static/js/tab_bar.js b/static/js/tab_bar.js
index 68b2f68bdf..4720244533 100644
--- a/static/js/tab_bar.js
+++ b/static/js/tab_bar.js
@@ -1,4 +1,4 @@
-var render_tab_bar = require('../templates/tab_bar.hbs');
+const render_tab_bar = require('../templates/tab_bar.hbs');
 
 function make_tab(title, hash, data, extra_class, home) {
     return {active: "inactive",
@@ -10,15 +10,15 @@ function make_tab(title, hash, data, extra_class, home) {
 }
 
 function make_tab_data() {
-    var tabs = [];
-    var filter = narrow_state.filter();
+    const tabs = [];
+    const filter = narrow_state.filter();
 
     function filtered_to_non_home_view_stream() {
         if (!filter.has_operator('stream')) {
             return false;
         }
-        var stream_name = filter.operands('stream')[0];
-        var stream_id = stream_data.get_stream_id(stream_name);
+        const stream_name = filter.operands('stream')[0];
+        const stream_id = stream_data.get_stream_id(stream_name);
         if (!stream_id) {
             return true;
         }
@@ -46,10 +46,10 @@ function make_tab_data() {
     }
 
     if (narrow_state.active() && narrow_state.operators().length > 0) {
-        var stream;
-        var ops = narrow_state.operators();
+        let stream;
+        const ops = narrow_state.operators();
         // Second breadcrumb item
-        var hashed = hash_util.operators_to_hash(ops.slice(0, 1));
+        let hashed = hash_util.operators_to_hash(ops.slice(0, 1));
         if (filter.has_operator("stream")) {
             stream = filter.operands("stream")[0];
             tabs.push(make_tab(stream, hashed, stream, 'stream'));
@@ -60,8 +60,8 @@ function make_tab_data() {
                                undefined, 'private_message '));
 
             if (filter.has_operator("pm-with")) {
-                var emails = filter.operands("pm-with")[0].split(',');
-                var names = _.map(emails, function (email) {
+                const emails = filter.operands("pm-with")[0].split(',');
+                const names = _.map(emails, function (email) {
                     if (!people.get_by_email(email)) {
                         return email;
                     }
@@ -88,7 +88,7 @@ function make_tab_data() {
         } else if (filter.has_operand("is", "mentioned")) {
             tabs.push(make_tab("Mentions", hashed));
         } else if (filter.has_operator("sender")) {
-            var sender = filter.operands("sender")[0];
+            let sender = filter.operands("sender")[0];
             if (people.get_by_email(sender)) {
                 sender = people.get_by_email(sender).full_name;
             }
@@ -102,7 +102,7 @@ function make_tab_data() {
         // Third breadcrumb item for stream-topic naarrows
         if (filter.has_operator("stream") &&
             filter.has_operator("topic")) {
-            var topic = filter.operands("topic")[0];
+            const topic = filter.operands("topic")[0];
             hashed = hash_util.operators_to_hash(ops.slice(0, 2));
 
             tabs.push(make_tab(topic, hashed, null));
@@ -120,17 +120,17 @@ function make_tab_data() {
 }
 
 exports.colorize_tab_bar = function () {
-    var stream_tab = $('#tab_list .stream');
+    const stream_tab = $('#tab_list .stream');
     if (stream_tab.length > 0) {
-        var stream_name = stream_tab.data('name');
+        let stream_name = stream_tab.data('name');
         if (stream_name === undefined) {
             return;
         }
         stream_name = stream_name.toString();
 
-        var color_for_stream = stream_data.get_color(stream_name);
-        var stream_dark = stream_color.get_color_class(color_for_stream);
-        var stream_light = colorspace.getHexColor(
+        const color_for_stream = stream_data.get_color(stream_name);
+        const stream_dark = stream_color.get_color_class(color_for_stream);
+        const stream_light = colorspace.getHexColor(
             colorspace.getLighterColor(
                 colorspace.getDecimalColor(color_for_stream), 0.2));
 
@@ -152,13 +152,13 @@ exports.colorize_tab_bar = function () {
 };
 
 function build_tab_bar() {
-    var tabs = make_tab_data();
+    const tabs = make_tab_data();
 
-    var tab_bar = $("#tab_bar");
+    const tab_bar = $("#tab_bar");
     tab_bar.empty();
 
     tabs[tabs.length - 1].active = "active";
-    var rendered =  render_tab_bar({tabs: tabs});
+    const rendered =  render_tab_bar({tabs: tabs});
 
     tab_bar.append(rendered);
     exports.colorize_tab_bar();
diff --git a/static/js/upload.js b/static/js/upload.js
index 1f8a0a3c64..1115eb66f9 100644
--- a/static/js/upload.js
+++ b/static/js/upload.js
@@ -14,13 +14,13 @@ exports.feature_check = function (upload_button) {
 };
 
 exports.options = function (config) {
-    var textarea;
-    var send_button;
-    var send_status;
-    var send_status_close;
-    var error_msg;
-    var upload_bar;
-    var file_input;
+    let textarea;
+    let send_button;
+    let send_status;
+    let send_status_close;
+    let error_msg;
+    let upload_bar;
+    let file_input;
 
     switch (config.mode) {
     case 'compose':
@@ -45,13 +45,13 @@ exports.options = function (config) {
         throw Error("Invalid upload mode!");
     }
 
-    var hide_upload_status = function () {
+    const hide_upload_status = function () {
         send_button.prop("disabled", false);
         send_status.removeClass("alert-info").hide();
         $('div.progress.active').remove();
     };
 
-    var drop = function () {
+    const drop = function () {
         send_button.attr("disabled", "");
         send_status.addClass("alert-info").show();
         send_status_close.one('click', function () {
@@ -62,7 +62,7 @@ exports.options = function (config) {
         });
     };
 
-    var uploadStarted = function (i, file) {
+    const uploadStarted = function (i, file) {
         error_msg.html($("<p>").text(i18n.t("Uploading…")));
         // file.lastModified is unique for each upload, and was previously used to track each
         // upload. But, when an image is pasted into Safari, it looks like the lastModified time
@@ -77,12 +77,12 @@ exports.options = function (config) {
         compose_ui.insert_syntax_and_focus("[Uploading " + file.name + "…]()", textarea);
     };
 
-    var progressUpdated = function (i, file, progress) {
+    const progressUpdated = function (i, file, progress) {
         $("#" + upload_bar + '-' + file.trackingId).width(progress + "%");
     };
 
-    var uploadError = function (error_code, server_response, file) {
-        var msg;
+    const uploadError = function (error_code, server_response, file) {
+        let msg;
         send_status.addClass("alert-error").removeClass("alert-info");
         send_button.prop("disabled", false);
         if (file !== undefined) {
@@ -99,7 +99,7 @@ exports.options = function (config) {
         case 'FileTooLarge':
             if (page_params.max_file_upload_size > 0) {
                 // sanitization not needed as the file name is not potentially parsed as HTML, etc.
-                var context = {
+                const context = {
                     file_name: file.name,
                     file_size: page_params.max_file_upload_size,
                 };
@@ -114,7 +114,7 @@ exports.options = function (config) {
             msg = i18n.t("Sorry, the file was too large.");
             break;
         case 400: {
-            var server_message = server_response && server_response.msg;
+            const server_message = server_response && server_response.msg;
             msg = server_message || i18n.t("An unknown error occurred.");
             break;
         }
@@ -125,12 +125,12 @@ exports.options = function (config) {
         error_msg.text(msg);
     };
 
-    var uploadFinished = function (i, file, response) {
+    const uploadFinished = function (i, file, response) {
         if (response.uri === undefined) {
             return;
         }
-        var split_uri = response.uri.split("/");
-        var filename = split_uri[split_uri.length - 1];
+        const split_uri = response.uri.split("/");
+        const filename = split_uri[split_uri.length - 1];
         // Urgh, yet another hack to make sure we're "composing"
         // when text gets added into the composebox.
         if (config.mode === 'compose' && !compose_state.composing()) {
@@ -140,15 +140,15 @@ exports.options = function (config) {
             textarea.focus();
         }
 
-        var uri = make_upload_absolute(response.uri);
+        const uri = make_upload_absolute(response.uri);
 
         if (i === -1) {
             // This is a paste, so there's no filename. Show the image directly
-            var pasted_image_uri = "[pasted image](" + uri + ")";
+            const pasted_image_uri = "[pasted image](" + uri + ")";
             compose_ui.replace_syntax("[Uploading " + file.name + "…]()", pasted_image_uri, textarea);
         } else {
             // This is a dropped file, so make the filename a link to the image
-            var filename_uri = "[" + filename + "](" + uri + ")";
+            const filename_uri = "[" + filename + "](" + uri + ")";
             compose_ui.replace_syntax("[Uploading " + file.name + "…]()", filename_uri, textarea);
         }
         compose_ui.autosize_textarea();