REFACTOR: Remove `_.findIndex`

REFACTOR: Remove _.findIndex

diff --git a/app/assets/javascripts/discourse/app/initializers/subscribe-user-notifications.js b/app/assets/javascripts/discourse/app/initializers/subscribe-user-notifications.js
index 53c6376..6281a7d 100644
--- a/app/assets/javascripts/discourse/app/initializers/subscribe-user-notifications.js
+++ b/app/assets/javascripts/discourse/app/initializers/subscribe-user-notifications.js
@@ -68,16 +68,15 @@ export default {
 
           if (stale && stale.hasResults && lastNotification) {
             const oldNotifications = stale.results.get("content");
-            const staleIndex = _.findIndex(oldNotifications, {
-              id: lastNotification.id
-            });
+            const staleIndex = oldNotifications.findIndex(
+              n => n.id === lastNotification.id
+            );
 
             if (staleIndex === -1) {
               // this gets a bit tricky, unread pms are bumped to front
               let insertPosition = 0;
               if (lastNotification.notification_type !== 6) {
-                insertPosition = _.findIndex(
-                  oldNotifications,
+                insertPosition = oldNotifications.findIndex(
                   n => n.notification_type !== 6 || n.read
                 );
                 insertPosition =
diff --git a/app/assets/javascripts/discourse/app/lib/topic-list-tracker.js b/app/assets/javascripts/discourse/app/lib/topic-list-tracker.js
index c6a5ac3..eee5501 100644
--- a/app/assets/javascripts/discourse/app/lib/topic-list-tracker.js
+++ b/app/assets/javascripts/discourse/app/lib/topic-list-tracker.js
@@ -46,7 +46,7 @@ export function setTopicId(topicId) {
 
 function currentIndex() {
   if (currentTopicId && model && model.topics) {
-    const idx = _.findIndex(model.topics, t => t.id === currentTopicId);
+    const idx = model.topics.findIndex(t => t.id === currentTopicId);
     if (idx > -1) {
       return idx;
     }

GitHub sha: 2353794a

This commit appears in #10566 which was merged by eviltrout.