diff --git a/frontend_tests/node_tests/common.js b/frontend_tests/node_tests/common.js
index 7e0909d017..fe75deb3dd 100644
--- a/frontend_tests/node_tests/common.js
+++ b/frontend_tests/node_tests/common.js
@@ -9,9 +9,9 @@ const $ = require("../zjsunit/zjquery");
 const noop = () => {};
 
 mock_esm("tippy.js", {
-    default: (selector) => {
-        $(selector)[0]._tippy = noop;
-        $(selector)[0]._tippy.setContent = noop;
+    default: (arg) => {
+        arg._tippy = {setContent: noop};
+        return arg._tippy;
     },
 });
 
diff --git a/static/js/blueslip.js b/static/js/blueslip.js
index e2dc380850..b3ef413309 100644
--- a/static/js/blueslip.js
+++ b/static/js/blueslip.js
@@ -90,11 +90,12 @@ function report_error(
     }
 
     const key = ":" + msg + stack;
+    const last_report_time = last_report_attempt.get(key);
     if (
         reported_errors.has(key) ||
-        (last_report_attempt.has(key) &&
+        (last_report_time !== undefined &&
             // Only try to report a given error once every 5 minutes
-            Date.now() - last_report_attempt.get(key) <= 60 * 5 * 1000)
+            Date.now() - last_report_time <= 60 * 5 * 1000)
     ) {
         return;
     }
diff --git a/static/js/common.js b/static/js/common.js
index 7c0173c73c..2db42774b0 100644
--- a/static/js/common.js
+++ b/static/js/common.js
@@ -71,8 +71,9 @@ export function adjust_mac_shortcuts(key_elem_class, require_cmd_style) {
         }
 
         for (const key of keys) {
-            if (keys_map.get(key)) {
-                key_text = key_text.replace(key, keys_map.get(key));
+            const replace_key = keys_map.get(key);
+            if (replace_key !== undefined) {
+                key_text = key_text.replace(key, replace_key);
             }
         }
 
@@ -85,10 +86,9 @@ export function adjust_mac_shortcuts(key_elem_class, require_cmd_style) {
 function set_password_toggle_label(password_selector, label, tippy_tooltips) {
     $(password_selector).attr("aria-label", label);
     if (tippy_tooltips) {
-        if (!$(password_selector)[0]._tippy) {
-            tippy(password_selector);
-        }
-        $(password_selector)[0]._tippy.setContent(label);
+        const element = $(password_selector)[0];
+        const tippy_instance = element._tippy ?? tippy(element);
+        tippy_instance.setContent(label);
     } else {
         $(password_selector).attr("title", label);
     }