Flow, coding style

react/features/base/conference/middleware.js

         let videoType;
 
         if ((participantById && participantById.local)
-            || (!id && pinnedParticipant && pinnedParticipant.local)) {
+                || (!id && pinnedParticipant && pinnedParticipant.local)) {
             videoType = 'local';
         } else {
             videoType = 'remote';

react/features/base/participants/actions.js

     };
 }
 
+/**
+ * Create an action for removing a participant from the conference.
+ *
+ * @param {string} id - Participant's ID.
+ * @returns {{
+ *     type: KICK_PARTICIPANT,
+ *     id: string
+ * }}
+ */
+export function kickParticipant(id) {
+    return {
+        type: KICK_PARTICIPANT,
+        id
+    };
+}
+
 /**
  * Creates an action to signal the connection status of the local participant
  * has changed.
 
         if (participant) {
             return dispatch(participantConnectionStatusChanged(
-                participant.id, connectionStatus));
+                participant.id,
+                connectionStatus));
         }
     };
 }
 
-/**
- * Create an action for removing a participant from the conference.
- *
- * @param {string} id - Participant's ID.
- * @returns {{
- *     type: KICK_PARTICIPANT,
- *     id: string
- * }}
- */
-export function kickParticipant(id) {
-    return {
-        type: KICK_PARTICIPANT,
-        id
-    };
-}
-
 /**
  * Action to signal that the ID of local participant has changed. It happens
  * when the local participant joins a new conference or leaves an existing
     });
 }
 
+/**
+ * Action to remove a local participant.
+ *
+ * @returns {Function}
+ */
+export function localParticipantLeft() {
+    return (dispatch, getState) => {
+        const participant = getLocalParticipant(getState);
+
+        if (participant) {
+            return dispatch(participantLeft(participant.id));
+        }
+    };
+}
+
 /**
  * Action to signal the role of the local participant has changed. It can happen
  * when the participant has joined a conference, even before a non-default local
     };
 }
 
-/**
- * Action to remove a local participant.
- *
- * @returns {Function}
- */
-export function localParticipantLeft() {
-    return (dispatch, getState) => {
-        const participant = getLocalParticipant(getState);
-
-        if (participant) {
-            return dispatch(participantLeft(participant.id));
-        }
-    };
-}
-
 /**
  * Action to signal that a participant's display name has changed.
  *

react/features/large-video/actions.js

  * @returns {(string|undefined)}
  */
 function _electParticipantInLargeVideo(state) {
-    // First get the pinned participant. If a participant is pinned, they will
-    // be shown in the LargeVideo.
+    // 1. If a participant is pinned, they will be shown in the LargeVideo (
+    //    regardless of whether they are local or remote).
     const participants = state['features/base/participants'];
     let participant = participants.find(p => p.pinned);
     let id = participant && participant.id;
 
     if (!id) {
-        // No participant is pinned so get the dominant speaker. But the local
-        // participant won't be displayed in LargeVideo even if he/she is the
-        // dominant speaker.
+        // 2. No participant is pinned so get the dominant speaker. But the
+        //    local participant won't be displayed in LargeVideo even if she is
+        //    the dominant speaker.
         participant = participants.find(p => p.dominantSpeaker && !p.local);
         id = participant && participant.id;
 
         if (!id) {
-            // There is no dominant speaker so select the participant which last
-            // had visible video (excluding ourselves).
+            // 3. There is no dominant speaker so select the remote participant
+            //    who last had visible video.
             const tracks = state['features/base/tracks'];
             const videoTrack = _electLastVisibleRemoteVideo(tracks);
 
             id = videoTrack && videoTrack.participantId;
 
             if (!id) {
-                // It's possible there is no participant with visible video,
-                // this can happen for a number or reasons:
-                //  - there is only one participant (the local user)
-                //  - other participants joined with video muted
-                // As a last resort, pick the last participant.
+                // 4. It's possible there is no participant with visible video.
+                //    This can happen for a number of reasons:
+                //    - there is only one participant (i.e. the local user),
+                //    - other participants joined with video muted.
+                //    As a last resort, pick the last participant who joined the
+                //    conference (regardless of whether they are local or
+                //    remote).
                 participant = participants[participants.length - 1];
                 id = participant && participant.id;
             }

react/features/large-video/middleware.js

+// @flow
+
 import {
     DOMINANT_SPEAKER_CHANGED,
     PARTICIPANT_JOINED,
     TRACK_UPDATED
 } from '../base/tracks';
 
-import {
-    selectParticipant,
-    selectParticipantInLargeVideo
-} from './actions';
+import { selectParticipant, selectParticipantInLargeVideo } from './actions';
 
 /**
  * Middleware that catches actions related to participants and tracks and
         store.dispatch(selectParticipantInLargeVideo());
         break;
 
-    case TRACK_UPDATED: {
+    case TRACK_UPDATED:
         // In order to minimize re-calculations, we need to select participant
         // only if the videoType of the current participant rendered in
         // LargeVideo has changed.
         }
         break;
     }
-    }
 
     return result;
 });

react/features/large-video/reducer.js

+// @flow
+
 import { PARTICIPANT_ID_CHANGED } from '../base/participants';
 import { ReducerRegistry } from '../base/redux';