diff --git a/react/features/base/jwt/components/CalleeInfo.js b/react/features/base/jwt/components/CalleeInfo.js
index 58cbec4e3..199d9a725 100644
--- a/react/features/base/jwt/components/CalleeInfo.js
+++ b/react/features/base/jwt/components/CalleeInfo.js
@@ -75,9 +75,9 @@ class CalleeInfo extends Component<Props, State> {
 
     _onLargeVideoAvatarVisible: Function;
 
-    _playAudioInterval: *;
+    _playAudioInterval: ?IntervalID;
 
-    _ringingTimeout: *;
+    _ringingTimeout: ?TimeoutID;
 
     _setAudio: Function;
 
diff --git a/react/features/calendar-sync/components/ConferenceNotification.native.js b/react/features/calendar-sync/components/ConferenceNotification.native.js
index 2128b7a4a..ab1023a44 100644
--- a/react/features/calendar-sync/components/ConferenceNotification.native.js
+++ b/react/features/calendar-sync/components/ConferenceNotification.native.js
@@ -64,7 +64,7 @@ type State = {
  * screen when another meeting is about to start.
  */
 class ConferenceNotification extends Component<Props, State> {
-    updateIntervalId: *;
+    updateIntervalId: IntervalID;
 
     /**
      * Constructor of the ConferenceNotification component.
diff --git a/react/features/overlay/components/AbstractPageReloadOverlay.js b/react/features/overlay/components/AbstractPageReloadOverlay.js
index eaceedc3b..d78d3d0d5 100644
--- a/react/features/overlay/components/AbstractPageReloadOverlay.js
+++ b/react/features/overlay/components/AbstractPageReloadOverlay.js
@@ -88,7 +88,7 @@ export default class AbstractPageReloadOverlay extends Component<*, *> {
                 || configError);
     }
 
-    _interval: *;
+    _interval: ?IntervalID;
 
     state: {
 
diff --git a/react/features/recording/components/RecordingLabel.web.js b/react/features/recording/components/RecordingLabel.web.js
index 69059384e..21fd30cb9 100644
--- a/react/features/recording/components/RecordingLabel.web.js
+++ b/react/features/recording/components/RecordingLabel.web.js
@@ -98,7 +98,7 @@ type State = {
  * @extends {Component}
  */
 class RecordingLabel extends AbstractRecordingLabel<Props, State> {
-    _autohideTimeout: *;
+    _autohideTimeout: TimeoutID;
 
     state = {
         hidden: false
diff --git a/react/features/speaker-stats/components/SpeakerStats.js b/react/features/speaker-stats/components/SpeakerStats.js
index f9f0c0cdc..e5a36d2a3 100644
--- a/react/features/speaker-stats/components/SpeakerStats.js
+++ b/react/features/speaker-stats/components/SpeakerStats.js
@@ -45,7 +45,7 @@ class SpeakerStats extends Component<*, *> {
         stats: {}
     };
 
-    _updateInterval: *;
+    _updateInterval: IntervalID;
 
     /**
      * Initializes a new SpeakerStats instance.